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  <xsd:element id="tslx_PercentageOfExcessPreIncentiveFeeNetInvestmentIncomeForImmediatePrecedingCalendarQuarter" name="PercentageOfExcessPreIncentiveFeeNetInvestmentIncomeForImmediatePrecedingCalendarQuarter" type="dtr-types:percentItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
  <xsd:element id="tslx_PercentageOfExcessPreIncentiveFeeNetInvestmentIncomePayableAfterHurdleRateReachedAndCatchUpAchieved" name="PercentageOfExcessPreIncentiveFeeNetInvestmentIncomePayableAfterHurdleRateReachedAndCatchUpAchieved" type="dtr-types:percentItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
  <xsd:element id="tslx_PercentageOfIncentiveFeeRate" name="PercentageOfIncentiveFeeRate" type="dtr-types:percentItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
  <xsd:element id="tslx_PercentageOfInvestmentsAtFairValue" name="PercentageOfInvestmentsAtFairValue" type="dtr-types:percentItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false"/>
  <xsd:element id="tslx_PercentageOfManagementFeeCalculatedOnGrossAssets" name="PercentageOfManagementFeeCalculatedOnGrossAssets" type="dtr-types:percentItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
  <xsd:element id="tslx_PercentageOfManagementFeeInExcessOfAnnualRateOnGrossAssets" name="PercentageOfManagementFeeInExcessOfAnnualRateOnGrossAssets" type="dtr-types:percentItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
  <xsd:element id="tslx_PercentageOfMinimumQualifyingAssetsToPurchaseNonQualifyingAssets" name="PercentageOfMinimumQualifyingAssetsToPurchaseNonQualifyingAssets" type="dtr-types:percentItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
  <xsd:element id="tslx_PercentageOfNetProceedsOfSaleOfEquityInterests" name="PercentageOfNetProceedsOfSaleOfEquityInterests" type="dtr-types:percentItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
  <xsd:element id="tslx_PercentageOfNonQualifyingAssets" name="PercentageOfNonQualifyingAssets" type="dtr-types:percentItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
  <xsd:element id="tslx_PercentageOfPreIncentiveFeeNetInvestmentIncomeAnnualizedAfterCatchUpAchieved" name="PercentageOfPreIncentiveFeeNetInvestmentIncomeAnnualizedAfterCatchUpAchieved" type="dtr-types:percentItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
  <xsd:element id="tslx_PercentageOfPreIncentiveFeeNetInvestmentIncomeHurdleRateQuarterly" name="PercentageOfPreIncentiveFeeNetInvestmentIncomeHurdleRateQuarterly" type="dtr-types:percentItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
  <xsd:element id="tslx_PercentageOfPreIncentiveFeeNetInvestmentIncomePayableAfterHurdleRateReachedAndCatchUpAchieved" name="PercentageOfPreIncentiveFeeNetInvestmentIncomePayableAfterHurdleRateReachedAndCatchUpAchieved" type="dtr-types:percentItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
  <xsd:element id="tslx_PercentageOfPreIncentiveFeeNetInvestmentIncomePayableQuarterly" name="PercentageOfPreIncentiveFeeNetInvestmentIncomePayableQuarterly" type="dtr-types:percentItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
  <xsd:element id="tslx_PercentageOfPreIncentiveFeeNetInvestmentIncomeQuarterlyAfterCatchUpAchieved" name="PercentageOfPreIncentiveFeeNetInvestmentIncomeQuarterlyAfterCatchUpAchieved" type="dtr-types:percentItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
  <xsd:element id="tslx_PercentageOfWeightedCumulativeRealizedCapitalGainsLessCumulativeRealizedCapitalLossesAndUnrealizedCapitalLosses" name="PercentageOfWeightedCumulativeRealizedCapitalGainsLessCumulativeRealizedCapitalLossesAndUnrealizedCapitalLosses" type="dtr-types:percentItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
  <xsd:element id="tslx_PercentageOfWeightedCumulativeRealizedCapitalGainsLessRealizedCapitalLossesAndUnrealizedCapitalLossesThroughMarch312014HurdleRate" name="PercentageOfWeightedCumulativeRealizedCapitalGainsLessRealizedCapitalLossesAndUnrealizedCapitalLossesThroughMarch312014HurdleRate" type="dtr-types:percentItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
  <xsd:element id="tslx_PerShareMarketValueAtEndPeriod" name="PerShareMarketValueAtEndPeriod" type="dtr-types:perShareItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
  <xsd:element id="tslx_ProceedsFromInvestmentsNet" name="ProceedsFromInvestmentsNet" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="debit"/>
  <xsd:element id="tslx_ProceedsFromSettlementsOfInterestRateSwapsExcludingUpfrontFees" name="ProceedsFromSettlementsOfInterestRateSwapsExcludingUpfrontFees" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="debit"/>
  <xsd:element id="tslx_ProceedsFromSettlementsOfInterestRateSwapsRelatedToConvertibleNotes" name="ProceedsFromSettlementsOfInterestRateSwapsRelatedToConvertibleNotes" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="debit"/>
  <xsd:element id="tslx_PurchaseCommitmentToFundInvestment" name="PurchaseCommitmentToFundInvestment" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false" xbrli:balance="credit"/>
  <xsd:element id="tslx_PurchasesAndOriginationsOfInvestmentsNet" name="PurchasesAndOriginationsOfInvestmentsNet" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="credit"/>
  <xsd:element id="tslx_RepaymentsOnInvestments" name="RepaymentsOnInvestments" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="credit"/>
  <xsd:element id="tslx_SwapSettlement" name="SwapSettlement" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="credit"/>
  <xsd:element id="tslx_TaxReclassificationOfStockholdersEquity" name="TaxReclassificationOfStockholdersEquity" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="credit"/>
  <xsd:element id="tslx_TotalReturnBasedOnMarketValue" name="TotalReturnBasedOnMarketValue" type="dtr-types:percentItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false"/>
  <xsd:element id="tslx_TotalReturnBasedOnMarketValueWithReinvestmentOfDividends" name="TotalReturnBasedOnMarketValueWithReinvestmentOfDividends" type="dtr-types:percentItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false"/>
  <xsd:element id="tslx_TotalReturnBasedOnNetAssetValue" name="TotalReturnBasedOnNetAssetValue" type="dtr-types:percentItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false"/>
  <xsd:element id="tslx_UnrealizedGainOnInvestments" name="UnrealizedGainOnInvestments" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="credit"/>
  <xsd:element id="tslx_UnrealizedLossOnInvestments" name="UnrealizedLossOnInvestments" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="debit"/>
  <xsd:element id="tslx_UpfrontPaymentsReceiptsInDerivativeAssetsAndLiabilities" name="UpfrontPaymentsReceiptsInDerivativeAssetsAndLiabilities" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="credit"/>
  <xsd:element id="tslx_EarningsPerShareBasicAndDilutedLineItems" name="EarningsPerShareBasicAndDilutedLineItems" type="xbrli:stringItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_AbilityToEnterIntoTransactionsWithAffiliatesIsRestrictedMember" name="AbilityToEnterIntoTransactionsWithAffiliatesIsRestrictedMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_AbilityToRaiseAdditionalCapitalDueToRegulationGovernanceOnBdcMember" name="AbilityToRaiseAdditionalCapitalDueToRegulationGovernanceOnBdcMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_ABLFILOTermLoanDueAprilTwoThousandTwentyFourMember" name="ABLFILOTermLoanDueAprilTwoThousandTwentyFourMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_ABLFILOTermLoanDueAprilTwoThousandTwentySevenMember" name="ABLFILOTermLoanDueAprilTwoThousandTwentySevenMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_AblFiloTermLoanDueAugustTwoThousandTwentySevenMember" name="AblFiloTermLoanDueAugustTwoThousandTwentySevenMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_ABLFILOTermLoanDueMayTwoThousandTwentyFiveMember" name="ABLFILOTermLoanDueMayTwoThousandTwentyFiveMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_ABLFILOTermLoanDueMayTwoThousandTwentySixMember" name="ABLFILOTermLoanDueMayTwoThousandTwentySixMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_ABLFILOTermLoanMember" name="ABLFILOTermLoanMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_AblFirstLienLoanDueAugustTwoThousandTwentyFiveMember" name="AblFirstLienLoanDueAugustTwoThousandTwentyFiveMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_AcceoSolutionsIncMember" name="AcceoSolutionsIncMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_AcousticLPMember" name="AcousticLPMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_AdministrationAgreementMember" name="AdministrationAgreementMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_AdviserMember" name="AdviserMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_AllegroCloLtdSeriesTwoThousandEighteenOneAMember" name="AllegroCloLtdSeriesTwoThousandEighteenOneAMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_AlphaMidcoIncMember" name="AlphaMidcoIncMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_AmericanAchievementCorpMember" name="AmericanAchievementCorpMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_AmericanMoneyManagementCorpCloLtdSeriesTwoThousandSixteenEighteenAMember" name="AmericanMoneyManagementCorpCloLtdSeriesTwoThousandSixteenEighteenAMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_AresCloLtdSeriesTwoThousandTwentyOneFiftyNineAMember" name="AresCloLtdSeriesTwoThousandTwentyOneFiftyNineAMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_AresLoanFundingILtdSeriesTwoThousandTwentyOneAlfaClassEMember" name="AresLoanFundingILtdSeriesTwoThousandTwentyOneAlfaClassEMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_AsgIiLlcMember" name="AsgIiLlcMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_AssetValuationWaterfallMember" name="AssetValuationWaterfallMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_Astra2LHoldingsIILLCMember" name="Astra2LHoldingsIILLCMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_AstraAcquisitionCorpMember" name="AstraAcquisitionCorpMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_AutomotiveMember" name="AutomotiveMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_AvidXchangeIncMember" name="AvidXchangeIncMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_AxonifyIncMember" name="AxonifyIncMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_BainCapitalCreditCLOLtdMember" name="BainCapitalCreditCLOLtdMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_BainCapitalCreditCLOLtdSeriesTwoThousandEighteenOneAMember" name="BainCapitalCreditCLOLtdSeriesTwoThousandEighteenOneAMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_BankBillSwapBidRateMember" name="BankBillSwapBidRateMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_BaseDividendMember" name="BaseDividendMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_BattalionCloLtdSeriesTwoThousandTwentyOneTwentyOneAMember" name="BattalionCloLtdSeriesTwoThousandTwentyOneTwentyOneAMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_BayshoreIntermediate2LPMember" name="BayshoreIntermediate2LPMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_BCTOAcePurchaserIncMember" name="BCTOAcePurchaserIncMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_BearOpCoLLCMember" name="BearOpCoLLCMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_BedBathAndBeyondIncMember" name="BedBathAndBeyondIncMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_BenefitStreetPartnersCloLtdSeriesTwoThousandFifteenBRMember" name="BenefitStreetPartnersCloLtdSeriesTwoThousandFifteenBRMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_BenefitStreetPartnersCloLtdSeriesTwoThousandFifteenEightAMember" name="BenefitStreetPartnersCloLtdSeriesTwoThousandFifteenEightAMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_BiohavenPharmaceuticalsIncMember" name="BiohavenPharmaceuticalsIncMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_BlackScholesModelMember" name="BlackScholesModelMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_BlueSnapIncMember" name="BlueSnapIncMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_BorrowMoneyWhichMagnifiesPotentialForGainOrLossAndIncreasesRiskOfInvestingMember" name="BorrowMoneyWhichMagnifiesPotentialForGainOrLossAndIncreasesRiskOfInvestingMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_BusinessServicesMember" name="BusinessServicesMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_CanadianDollarOfferedRateMember" name="CanadianDollarOfferedRateMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_CapitalGainsAccrueFollowingMarchThirtyFirstTwoThousandFourteenMember" name="CapitalGainsAccrueFollowingMarchThirtyFirstTwoThousandFourteenMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_CarisLifeSciencesIncMember" name="CarisLifeSciencesIncMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_CarlstarGroupLLCMember" name="CarlstarGroupLLCMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_CarlyleGlobalMarketStrategiesCLOLtdMember" name="CarlyleGlobalMarketStrategiesCLOLtdMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_CarlyleGlobalMarketStrategiesCLOLtdSeriesTwoThousandEighteenOneAMember" name="CarlyleGlobalMarketStrategiesCLOLtdSeriesTwoThousandEighteenOneAMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_CarlyleGlobalMarketStrategiesCloLtdSeriesTwoThousandFourteenFourRaMember" name="CarlyleGlobalMarketStrategiesCloLtdSeriesTwoThousandFourteenFourRaMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_CarlyleGlobalMarketStrategiesCLOLtdSeriesTwoThousandSeventeenFourAMember" name="CarlyleGlobalMarketStrategiesCLOLtdSeriesTwoThousandSeventeenFourAMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_CarvalCloIiiLtdSeriesTwoThousandNineteenTwoAMember" name="CarvalCloIiiLtdSeriesTwoThousandNineteenTwoAMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_CedarFundingCloLtdSeriesTwoThousandEighteenSevenAMember" name="CedarFundingCloLtdSeriesTwoThousandEighteenSevenAMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_CeltraTechnologiesIncMember" name="CeltraTechnologiesIncMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_ChemicalsMember" name="ChemicalsMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_CifcCloLimitedSeriesTwoThousandAndTwentyOneFourAMember" name="CifcCloLimitedSeriesTwoThousandAndTwentyOneFourAMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_CifcCloLtdSeriesTwoThousandEighteenThreeAMember" name="CifcCloLtdSeriesTwoThousandEighteenThreeAMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_ClassAOneUnitsMember" name="ClassAOneUnitsMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_ClassATwoUnitsMember" name="ClassATwoUnitsMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_ClassAUnitsMember" name="ClassAUnitsMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_ClassBUnitsMember" name="ClassBUnitsMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_ClassCOneUnitsMember" name="ClassCOneUnitsMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_ClearCompanyLLCMember" name="ClearCompanyLLCMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_ClinicientIncMember" name="ClinicientIncMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_CommonUnitsMember" name="CommonUnitsMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_CommunicationsMember" name="CommunicationsMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_ControlledAffiliatedInvestmentsMember" name="ControlledAffiliatedInvestmentsMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_ConvertibleNoteDueJuneTwentyTwentySevenMember" name="ConvertibleNoteDueJuneTwentyTwentySevenMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_ConvertibleNoteDueMayTwoThousandTwentyEightMember" name="ConvertibleNoteDueMayTwoThousandTwentyEightMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_ConvertibleNoteDueMayTwoThousandTwentyEightOneMember" name="ConvertibleNoteDueMayTwoThousandTwentyEightOneMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_ConvertibleNoteDueSeptemberTwoThousandTwentyThreeMember" name="ConvertibleNoteDueSeptemberTwoThousandTwentyThreeMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_CopperBidcoLLCMember" name="CopperBidcoLLCMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_CordanceOperationsLlcMember" name="CordanceOperationsLlcMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_CostModelMember" name="CostModelMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_CrownPointCloLtdSeriesTwoThousandTwentyOneTenAMember" name="CrownPointCloLtdSeriesTwoThousandTwentyOneTenAMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_CrunchtimeInformationSystemsIncMember" name="CrunchtimeInformationSystemsIncMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_DaySmartHoldingsLLCMember" name="DaySmartHoldingsLLCMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_DelayedDrawAndRevolverMember" name="DelayedDrawAndRevolverMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_DelayedDrawMember" name="DelayedDrawMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_DerivativeAssetInterestRateSwapEightMember" name="DerivativeAssetInterestRateSwapEightMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_DerivativeAssetInterestRateSwapElevenMember" name="DerivativeAssetInterestRateSwapElevenMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_DerivativeAssetInterestRateSwapFiveMember" name="DerivativeAssetInterestRateSwapFiveMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_DerivativeAssetInterestRateSwapFourMember" name="DerivativeAssetInterestRateSwapFourMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_DerivativeAssetInterestRateSwapMember" name="DerivativeAssetInterestRateSwapMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_DerivativeAssetInterestRateSwapNineMember" name="DerivativeAssetInterestRateSwapNineMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_DerivativeAssetInterestRateSwapOneMember" name="DerivativeAssetInterestRateSwapOneMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_DerivativeAssetInterestRateSwapSevenMember" name="DerivativeAssetInterestRateSwapSevenMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_DerivativeAssetInterestRateSwapSixMember" name="DerivativeAssetInterestRateSwapSixMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_DerivativeAssetInterestRateSwapTenMember" name="DerivativeAssetInterestRateSwapTenMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_DerivativeAssetInterestRateSwapThreeMember" name="DerivativeAssetInterestRateSwapThreeMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_DerivativeAssetInterestRateSwapTwoMember" name="DerivativeAssetInterestRateSwapTwoMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_DerivativeLiabilitiesInterestRateSwapMember" name="DerivativeLiabilitiesInterestRateSwapMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_DerivativeLiabilitiesInterestRateSwapOneMember" name="DerivativeLiabilitiesInterestRateSwapOneMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_DerivativeLiabilitiesInterestRateSwapThreeMember" name="DerivativeLiabilitiesInterestRateSwapThreeMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_DerivativeLiabilitiesInterestRateSwapTwoMember" name="DerivativeLiabilitiesInterestRateSwapTwoMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_DesignerBrandsIncMember" name="DesignerBrandsIncMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_DestinySolutionsParentHoldingCompanyMember" name="DestinySolutionsParentHoldingCompanyMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_DrydenSeniorLoanFundSeriesTwoThousandEighteenFiftyFiveAMember" name="DrydenSeniorLoanFundSeriesTwoThousandEighteenFiftyFiveAMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_DrydenSeniorLoanFundSeriesTwoThousandTwentyEightySixAMember" name="DrydenSeniorLoanFundSeriesTwoThousandTwentyEightySixAMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_DyeDurhamCorpMember" name="DyeDurhamCorpMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_DyeDurhamLtdMember" name="DyeDurhamLtdMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_EatonCloLtdSeriesTwoThousandFifteenOneAMember" name="EatonCloLtdSeriesTwoThousandFifteenOneAMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_EatonCloLtdSeriesTwoThousandTwentyOneAMember" name="EatonCloLtdSeriesTwoThousandTwentyOneAMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_EDBParentLLCMember" name="EDBParentLLCMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_EducationMember" name="EducationMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_ElysianFincoLtdMember" name="ElysianFincoLtdMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_EmploymentHeroHoldingsPtyLtdMember" name="EmploymentHeroHoldingsPtyLtdMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_EMSLinqIncMember" name="EMSLinqIncMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_EquityAndOtherInvestmentsMember" name="EquityAndOtherInvestmentsMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_ErlingLuxBidcoSarlMember" name="ErlingLuxBidcoSarlMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_EuroInterbankOfferRateMember" name="EuroInterbankOfferRateMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_ExtraHopNetworksIncMember" name="ExtraHopNetworksIncMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_FinancialServicesMember" name="FinancialServicesMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_FirstLienDebtInvestmentsMember" name="FirstLienDebtInvestmentsMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_FirstLienLoanDueAprilTwoThousandTwentyFiveMember" name="FirstLienLoanDueAprilTwoThousandTwentyFiveMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_FirstLienLoanDueAprilTwoThousandTwentyFiveOneMember" name="FirstLienLoanDueAprilTwoThousandTwentyFiveOneMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_FirstLienLoanDueAprilTwoThousandTwentyFiveTwoMember" name="FirstLienLoanDueAprilTwoThousandTwentyFiveTwoMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_FirstLienLoanDueAprilTwoThousandTwentyFourMember" name="FirstLienLoanDueAprilTwoThousandTwentyFourMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_FirstLienLoanDueAprilTwoThousandTwentySevenMember" name="FirstLienLoanDueAprilTwoThousandTwentySevenMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_FirstLienLoanDueAprilTwoThousandTwentySixMember" name="FirstLienLoanDueAprilTwoThousandTwentySixMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_FirstLienLoanDueAprilTwoThousandTwentyThreeMember" name="FirstLienLoanDueAprilTwoThousandTwentyThreeMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_FirstLienLoanDueAugustTwoThousandTwentyFiveMember" name="FirstLienLoanDueAugustTwoThousandTwentyFiveMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_FirstLienLoanDueAugustTwoThousandTwentyFiveOneMember" name="FirstLienLoanDueAugustTwoThousandTwentyFiveOneMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_FirstLienLoanDueAugustTwoThousandTwentySixMember" name="FirstLienLoanDueAugustTwoThousandTwentySixMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_FirstLienLoanDueAugustTwoThousandTwentySixOneMember" name="FirstLienLoanDueAugustTwoThousandTwentySixOneMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_FirstLienLoanDueAugustTwoThousandTwentyTwoMember" name="FirstLienLoanDueAugustTwoThousandTwentyTwoMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_FirstLienLoanDueDecemberTwentyTwentyFiveMember" name="FirstLienLoanDueDecemberTwentyTwentyFiveMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_FirstLienLoanDueDecemberTwoThousandTwentyFiveOneMember" name="FirstLienLoanDueDecemberTwoThousandTwentyFiveOneMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_FirstLienLoanDueDecemberTwoThousandTwentyFiveTwoMember" name="FirstLienLoanDueDecemberTwoThousandTwentyFiveTwoMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_FirstLienLoanDueDecemberTwoThousandTwentyFourMember" name="FirstLienLoanDueDecemberTwoThousandTwentyFourMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_FirstLienLoanDueDecemberTwoThousandTwentySevenMember" name="FirstLienLoanDueDecemberTwoThousandTwentySevenMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_FirstLienLoanDueDecemberTwoThousandTwentySevenOneMember" name="FirstLienLoanDueDecemberTwoThousandTwentySevenOneMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_FirstLienLoanDueDecemberTwoThousandTwentySevenTwoMember" name="FirstLienLoanDueDecemberTwoThousandTwentySevenTwoMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_FirstLienLoanDueDecemberTwoThousandTwentySixMember" name="FirstLienLoanDueDecemberTwoThousandTwentySixMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_FirstLienLoanDueDecemberTwoThousandTwentySixOneMember" name="FirstLienLoanDueDecemberTwoThousandTwentySixOneMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_FirstLienLoanDueDecemberTwoThousandTwentySixThreeMember" name="FirstLienLoanDueDecemberTwoThousandTwentySixThreeMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_FirstLienLoanDueDecemberTwoThousandTwentyThreeMember" name="FirstLienLoanDueDecemberTwoThousandTwentyThreeMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_FirstLienLoanDueDecemberTwoThousandTwentyTwoMember" name="FirstLienLoanDueDecemberTwoThousandTwentyTwoMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_FirstLienLoanDueFebruaryTwoThousandTwentySevenMember" name="FirstLienLoanDueFebruaryTwoThousandTwentySevenMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_FirstLienLoanDueFebruaryTwoThousandTwentySixMember" name="FirstLienLoanDueFebruaryTwoThousandTwentySixMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_FirstLienLoanDueJanuaryTwoThousandTwentyEightMember" name="FirstLienLoanDueJanuaryTwoThousandTwentyEightMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_FirstLienLoanDueJanuaryTwoThousandTwentyFourMember" name="FirstLienLoanDueJanuaryTwoThousandTwentyFourMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_FirstLienLoanDueJulyTwentyTwentyFourMember" name="FirstLienLoanDueJulyTwentyTwentyFourMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_FirstLienLoanDueJulyTwoThousandTwentyEightMember" name="FirstLienLoanDueJulyTwoThousandTwentyEightMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_FirstLienLoanDueJulyTwoThousandTwentyFiveMember" name="FirstLienLoanDueJulyTwoThousandTwentyFiveMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_FirstLienLoanDueJulyTwoThousandTwentySevenMember" name="FirstLienLoanDueJulyTwoThousandTwentySevenMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_FirstLienLoanDueJulyTwoThousandTwentyTwoMember" name="FirstLienLoanDueJulyTwoThousandTwentyTwoMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_FirstLienLoanDueJuneTwoThousandTwentyEightMember" name="FirstLienLoanDueJuneTwoThousandTwentyEightMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_FirstLienLoanDueJuneTwoThousandTwentyNineMember" name="FirstLienLoanDueJuneTwoThousandTwentyNineMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_FirstLienLoanDueJuneTwoThousandTwentySixMember" name="FirstLienLoanDueJuneTwoThousandTwentySixMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_FirstLienLoanDueJuneTwoThousandTwentySixOneMember" name="FirstLienLoanDueJuneTwoThousandTwentySixOneMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_FirstLienLoanDueJuneTwoThousandTwentyThreeMember" name="FirstLienLoanDueJuneTwoThousandTwentyThreeMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_FirstLienLoanDueJuneTwoThousandTwentyTwoMember" name="FirstLienLoanDueJuneTwoThousandTwentyTwoMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_FirstLienLoanDueMarchTwentyTwentyFourMember" name="FirstLienLoanDueMarchTwentyTwentyFourMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_FirstLienLoanDueMarchTwentyTwentySixMember" name="FirstLienLoanDueMarchTwentyTwentySixMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_FirstLienLoanDueMarchTwoThousandTwentyNineMember" name="FirstLienLoanDueMarchTwoThousandTwentyNineMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_FirstLienLoanDueMarchTwoThousandTwentySixMember" name="FirstLienLoanDueMarchTwoThousandTwentySixMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_FirstLienLoanDueMayTwoThousandTwentyEightMember" name="FirstLienLoanDueMayTwoThousandTwentyEightMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_FirstLienLoanDueMayTwoThousandTwentyFourMember" name="FirstLienLoanDueMayTwoThousandTwentyFourMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_FirstLienLoanDueMayTwoThousandTwentyNineMember" name="FirstLienLoanDueMayTwoThousandTwentyNineMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_FirstLienLoanDueMayTwoThousandTwentySevenMember" name="FirstLienLoanDueMayTwoThousandTwentySevenMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_FirstLienLoanDueMayTwoThousandTwentySixMember" name="FirstLienLoanDueMayTwoThousandTwentySixMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_FirstLienLoanDueNovemberTwoThousandTwentySevenMember" name="FirstLienLoanDueNovemberTwoThousandTwentySevenMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_FirstLienLoanDueNovemberTwoThousandTwentySixMember" name="FirstLienLoanDueNovemberTwoThousandTwentySixMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_FirstLienLoanDueOctoberTwoThousandTwentyEightMember" name="FirstLienLoanDueOctoberTwoThousandTwentyEightMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_FirstLienLoanDueOctoberTwoThousandTwentyFiveMember" name="FirstLienLoanDueOctoberTwoThousandTwentyFiveMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_FirstLienLoanDueOctoberTwoThousandTwentyFourMember" name="FirstLienLoanDueOctoberTwoThousandTwentyFourMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_FirstLienLoanDueOctoberTwoThousandTwentyFourOneMember" name="FirstLienLoanDueOctoberTwoThousandTwentyFourOneMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_FirstLienLoanDueOctoberTwoThousandTwentyFourTwoMember" name="FirstLienLoanDueOctoberTwoThousandTwentyFourTwoMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_FirstLienLoanDueOctoberTwoThousandTwentySixMember" name="FirstLienLoanDueOctoberTwoThousandTwentySixMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_FirstLienLoanDueOctoberTwoThousandTwentySixOneMember" name="FirstLienLoanDueOctoberTwoThousandTwentySixOneMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_FirstLienLoanDueOctoberTwoThousandTwentyTwoMember" name="FirstLienLoanDueOctoberTwoThousandTwentyTwoMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_FirstLienLoanDueSeptemberTwoThousandTwentyEightOneMember" name="FirstLienLoanDueSeptemberTwoThousandTwentyEightOneMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_FirstLienLoanDueSeptemberTwoThousandTwentyEightTwoMember" name="FirstLienLoanDueSeptemberTwoThousandTwentyEightTwoMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_FirstLienLoanDueSeptemberTwoThousandTwentySixMember" name="FirstLienLoanDueSeptemberTwoThousandTwentySixMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_FirstLienLoanDueSeptemberTwoThousandTwentySixOneMember" name="FirstLienLoanDueSeptemberTwoThousandTwentySixOneMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_FirstLienLoanDueSeptemberTwoThousandTwentySixThreeMember" name="FirstLienLoanDueSeptemberTwoThousandTwentySixThreeMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_FirstLienLoanDueSeptemberTwoThousandTwentySixTwoMember" name="FirstLienLoanDueSeptemberTwoThousandTwentySixTwoMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_FirstLienLoanDueSeptemberTwoThousandTwentyThreeMember" name="FirstLienLoanDueSeptemberTwoThousandTwentyThreeMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_FirstLienLoanDueSeptemberTwoThousandTwentyThreeOneMember" name="FirstLienLoanDueSeptemberTwoThousandTwentyThreeOneMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_FirstLienNoteDueJuneTwoThousandTwentyFourMember" name="FirstLienNoteDueJuneTwoThousandTwentyFourMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_FirstLienNoteDueMarchTwoThousandTwentyNineMember" name="FirstLienNoteDueMarchTwoThousandTwentyNineMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_FirstLienRevolvingLoanAprilTwoThousandTwentyFiveMember" name="FirstLienRevolvingLoanAprilTwoThousandTwentyFiveMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_FirstLienRevolvingLoanAprilTwoThousandTwentyFiveOneMember" name="FirstLienRevolvingLoanAprilTwoThousandTwentyFiveOneMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_FirstLienRevolvingLoanDueMayTwoThousandTwentyFourMember" name="FirstLienRevolvingLoanDueMayTwoThousandTwentyFourMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_FirstLienRevolvingLoanJuneTwoThousandTwentyThreeMember" name="FirstLienRevolvingLoanJuneTwoThousandTwentyThreeMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_FirstLienRevolvingLoanJuneTwoThousandTwentyTwoMember" name="FirstLienRevolvingLoanJuneTwoThousandTwentyTwoMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_FirstLienRevolvingLoanMayTwoThousandTwentyFourMember" name="FirstLienRevolvingLoanMayTwoThousandTwentyFourMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_FirstLienRevolvingLoanOctoberTwoThousandTwentyFiveMember" name="FirstLienRevolvingLoanOctoberTwoThousandTwentyFiveMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_FirstLienRevolvingLoanOctoberTwoThousandTwentyTwoMember" name="FirstLienRevolvingLoanOctoberTwoThousandTwentyTwoMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_ForeScoutTechnologiesIncMember" name="ForeScoutTechnologiesIncMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_FrontlineTechnologiesGroupLLCMember" name="FrontlineTechnologiesGroupLLCMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_GoldentreeCloLtdSeriesTwoThousandTwentySevenAMember" name="GoldentreeCloLtdSeriesTwoThousandTwentySevenAMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_GTreasurySSLLCMember" name="GTreasurySSLLCMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_GulfStreamMeridianSeriesTwoThousandTwentyOneFourAMember" name="GulfStreamMeridianSeriesTwoThousandTwentyOneFourAMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_GulfStreamMeridianSeriesTwoThousandTwentyOneSixAMember" name="GulfStreamMeridianSeriesTwoThousandTwentyOneSixAMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_HigherLogicLLCMember" name="HigherLogicLLCMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_HomecareSoftwareSolutionsLLCMember" name="HomecareSoftwareSolutionsLLCMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_HotelGamingAndLeisureMember" name="HotelGamingAndLeisureMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_HumanResourceSupportServicesMember" name="HumanResourceSupportServicesMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_IbisIntermediateCoMember" name="IbisIntermediateCoMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_IbisUSBlockerCoMember" name="IbisUSBlockerCoMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_IlluminateEducationIncMember" name="IlluminateEducationIncMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_IndebtednessCouldAdverselyAffectBusinessFinancialConditionsOrResultsOfOperationsMember" name="IndebtednessCouldAdverselyAffectBusinessFinancialConditionsOrResultsOfOperationsMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_InformationClearinghouseLLCAndMSMarketServiceLLCMember" name="InformationClearinghouseLLCAndMSMarketServiceLLCMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_IntegratedPracticeSolutionsIncMember" name="IntegratedPracticeSolutionsIncMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_IntelePeerHoldingsIncMember" name="IntelePeerHoldingsIncMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_InterestRateSwapEightMember" name="InterestRateSwapEightMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_InterestRateSwapElevenMember" name="InterestRateSwapElevenMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_InterestRateSwapFiveMember" name="InterestRateSwapFiveMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_InterestRateSwapFourMember" name="InterestRateSwapFourMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_InterestRateSwapNineMember" name="InterestRateSwapNineMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_InterestRateSwapOneMember" name="InterestRateSwapOneMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_InterestRateSwapSevenMember" name="InterestRateSwapSevenMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_InterestRateSwapSixMember" name="InterestRateSwapSixMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_InterestRateSwapTenMember" name="InterestRateSwapTenMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_InterestRateSwapThirteenMember" name="InterestRateSwapThirteenMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_InterestRateSwapThreeMember" name="InterestRateSwapThreeMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_InterestRateSwapTwelveMember" name="InterestRateSwapTwelveMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_InterestRateSwapTwoMember" name="InterestRateSwapTwoMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_InternetServicesMember" name="InternetServicesMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_InvestmentAdvisoryAgreementMember" name="InvestmentAdvisoryAgreementMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_IRGSEHoldingCorpMember" name="IRGSEHoldingCorpMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_JeffersonMillCloLtdSeriesTwoThousandFifteenOneAMember" name="JeffersonMillCloLtdSeriesTwoThousandFifteenOneAMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_JonasCollectionsAndRecoveryIncMember" name="JonasCollectionsAndRecoveryIncMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_KkrCloLtdFortyNineAMember" name="KkrCloLtdFortyNineAMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_KyribaCorpMember" name="KyribaCorpMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_LeantaasHoldingsIncMember" name="LeantaasHoldingsIncMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_LegislationAllowsToIncurAdditionalLeverageMember" name="LegislationAllowsToIncurAdditionalLeverageMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_LeverageWaiverMember" name="LeverageWaiverMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_LithiumTechnologiesLLCMember" name="LithiumTechnologiesLLCMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_LucidworksIncMember" name="LucidworksIncMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_MadisonParkCloSeriesTwoThousandEighteenTwentyEightAMember" name="MadisonParkCloSeriesTwoThousandEighteenTwentyEightAMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_MagnetiteCloLtdSeriesTwoThousandTwentyOneThirtyAMember" name="MagnetiteCloLtdSeriesTwoThousandTwentyOneThirtyAMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_MarketingServicesMember" name="MarketingServicesMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_MDAmericaEnergyLimitedLiabilityCompanyMember" name="MDAmericaEnergyLimitedLiabilityCompanyMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_MDAmericaEnergyLLCMember" name="MDAmericaEnergyLLCMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_MembershipInterestMember" name="MembershipInterestMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_MerativeLPMember" name="MerativeLPMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_MezzanineDebtInvestmentsMember" name="MezzanineDebtInvestmentsMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_MidoceanCreditCloLtdSeries20189AMember" name="MidoceanCreditCloLtdSeries20189AMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_MidoceanCreditCloLtdSeriesTwoThousandSixteenSixAMember" name="MidoceanCreditCloLtdSeriesTwoThousandSixteenSixAMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_MidwestMember" name="MidwestMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_MississippiResourcesLLCMember" name="MississippiResourcesLLCMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_MitnickCorporatePurchaserIncMember" name="MitnickCorporatePurchaserIncMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_MitnickTaAggregatorLpMember" name="MitnickTaAggregatorLpMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_ModernHireIncMember" name="ModernHireIncMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_MoranFoodsLLCMember" name="MoranFoodsLLCMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_MurchisonOilAndGasLlcMember" name="MurchisonOilAndGasLlcMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_NetwrixCorpMember" name="NetwrixCorpMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_NeuintelLLCMember" name="NeuintelLLCMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_NewportParentHoldingsLPMember" name="NewportParentHoldingsLPMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_NinetyNineCentsOnlyStoresLLCMember" name="NinetyNineCentsOnlyStoresLLCMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_NonControlledAffiliatedInvestmentsMember" name="NonControlledAffiliatedInvestmentsMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_NonControlledNonAffiliatedInvestmentsMember" name="NonControlledNonAffiliatedInvestmentsMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_NortheastMember" name="NortheastMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_Octagon57LlcSeries20211AMember" name="Octagon57LlcSeries20211AMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_OctagonInvestmentPartnersEighteenLimitedSeriesTwoThousandEighteenEighteenAMember" name="OctagonInvestmentPartnersEighteenLimitedSeriesTwoThousandEighteenEighteenAMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_OctagonInvestmentPartnersThirtyEightLtdSeriesTwoThousandEighteenOneAMember" name="OctagonInvestmentPartnersThirtyEightLtdSeriesTwoThousandEighteenOneAMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_OfficeProductsMember" name="OfficeProductsMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_OilGasAndConsumableFuelsMember" name="OilGasAndConsumableFuelsMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_OmnigoSoftwareLLCMember" name="OmnigoSoftwareLLCMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_OtherInvestmentMember" name="OtherInvestmentMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_OtherMember" name="OtherMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_OxfordSquareCapitalCorpMember" name="OxfordSquareCapitalCorpMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_PageUpPeopleLtdMember" name="PageUpPeopleLtdMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_ParkAvenueInstitutionalAdvisersCloLtdSeriesTwoThousandEighteenOneAMember" name="ParkAvenueInstitutionalAdvisersCloLtdSeriesTwoThousandEighteenOneAMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_PassportLabsIncMember" name="PassportLabsIncMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_PayScaleHoldingsIncMember" name="PayScaleHoldingsIncMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_PharmaceuticalsMember" name="PharmaceuticalsMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_PianoSoftwareIncMember" name="PianoSoftwareIncMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_PikesPeakCloSeriesTwoThousandTwentyOneNineAMember" name="PikesPeakCloSeriesTwoThousandTwentyOneNineAMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_PreferredUnitsMember" name="PreferredUnitsMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_PrimePayIntermediateLLCMember" name="PrimePayIntermediateLLCMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_PrimeRevenueIncMember" name="PrimeRevenueIncMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_Project44IncMember" name="Project44IncMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_ProjectPIntermediate2LLCMember" name="ProjectPIntermediate2LLCMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_RealizedCapitalGainsAccruedBeginningAprilFirstTwoThousandFourteenMember" name="RealizedCapitalGainsAccruedBeginningAprilFirstTwoThousandFourteenMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_RealizedCapitalGainsAccruedPriorToMarchThirtyFirstTwoThousandFourteenMember" name="RealizedCapitalGainsAccruedPriorToMarchThirtyFirstTwoThousandFourteenMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_ReliaQuestHoldingsLLCMember" name="ReliaQuestHoldingsLLCMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_ReliaQuestLLCMember" name="ReliaQuestLLCMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_RetailAndConsumerProductsMember" name="RetailAndConsumerProductsMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_RevolverMember" name="RevolverMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_RevolvingCreditFacilityMaturityOnApril232027Member" name="RevolvingCreditFacilityMaturityOnApril232027Member" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_RevolvingCreditFacilityMaturityOnFebruary42026Member" name="RevolvingCreditFacilityMaturityOnFebruary42026Member" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_RevolvingCreditFacilityMaturityOnJanuary312025Member" name="RevolvingCreditFacilityMaturityOnJanuary312025Member" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_RisksAssociatedWithChangesInInterestRatesMember" name="RisksAssociatedWithChangesInInterestRatesMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_RisksAssociatedWithConflictsOfInterestMember" name="RisksAssociatedWithConflictsOfInterestMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_RMCFIVCIVXXXVLPMember" name="RMCFIVCIVXXXVLPMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_RRLtdSeriesTwoThousandTwentyEightAMember" name="RRLtdSeriesTwoThousandTwentyEightAMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_SecondLienDebtInvestmentsMember" name="SecondLienDebtInvestmentsMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_SecondLienLoanDueOctoberTwoThousandTwentyNineMember" name="SecondLienLoanDueOctoberTwoThousandTwentyNineMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_SecuredOvernightFinancingRateMember" name="SecuredOvernightFinancingRateMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_SeriesAPreferredUnitsMember" name="SeriesAPreferredUnitsMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_SeriesCOnePreferredSharesMember" name="SeriesCOnePreferredSharesMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_ShackeltonCloLtdSeries20157RaMember" name="ShackeltonCloLtdSeries20157RaMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_SignalPeakCloLLCSeriesTwoThousandEighteenFiveAMember" name="SignalPeakCloLLCSeriesTwoThousandEighteenFiveAMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_SMPAHoldingsLLCMember" name="SMPAHoldingsLLCMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_SouthMember" name="SouthMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_SouthwickParkCloLtdSeries20194AMember" name="SouthwickParkCloLtdSeries20194AMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_SpecialDividendMember" name="SpecialDividendMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_SprinklrIncMember" name="SprinklrIncMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_SterlingOvernightInterbankAverageRateMember" name="SterlingOvernightInterbankAverageRateMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_StewartParkCloLtdSeriesTwoThousandFifteenOneAMember" name="StewartParkCloLtdSeriesTwoThousandFifteenOneAMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_StructuredProductDueAprilTwoThousandThirtyFourMember" name="StructuredProductDueAprilTwoThousandThirtyFourMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_StructuredProductDueAprilTwoThousandThirtyOneMember" name="StructuredProductDueAprilTwoThousandThirtyOneMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_StructuredProductDueAprilTwoThousandThirtySixMember" name="StructuredProductDueAprilTwoThousandThirtySixMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_StructuredProductDueAprilTwoThousandThirtyThreeMember" name="StructuredProductDueAprilTwoThousandThirtyThreeMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_StructuredProductDueJanuaryTwoThousandThirtyMember" name="StructuredProductDueJanuaryTwoThousandThirtyMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_StructuredProductDueJanuaryTwoThousandThirtyOneMember" name="StructuredProductDueJanuaryTwoThousandThirtyOneMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_StructuredProductDueJanuaryTwoThousandThirtySevenMember" name="StructuredProductDueJanuaryTwoThousandThirtySevenMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_StructuredProductDueJulyTwoThousandThirtyFiveMember" name="StructuredProductDueJulyTwoThousandThirtyFiveMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_StructuredProductDueJulyTwoThousandThirtyFourMember" name="StructuredProductDueJulyTwoThousandThirtyFourMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_StructuredProductDueJulyTwoThousandThirtyMember" name="StructuredProductDueJulyTwoThousandThirtyMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_StructuredProductDueJulyTwoThousandThirtyOneMember" name="StructuredProductDueJulyTwoThousandThirtyOneMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_StructuredProductDueJulyTwoThousandThirtySixMember" name="StructuredProductDueJulyTwoThousandThirtySixMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_StructuredProductDueJulyTwoThousandThirtyThreeMember" name="StructuredProductDueJulyTwoThousandThirtyThreeMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_StructuredProductDueJulyTwoThousandThirtyTwoMember" name="StructuredProductDueJulyTwoThousandThirtyTwoMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_StructuredProductDueJuneTwoThousandThirtyOneMember" name="StructuredProductDueJuneTwoThousandThirtyOneMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_StructuredProductDueMayTwoThousandThirtyOneMember" name="StructuredProductDueMayTwoThousandThirtyOneMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_StructuredProductDueOctoberTwoThousandThirtyFourMember" name="StructuredProductDueOctoberTwoThousandThirtyFourMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_StructuredProductDueOctoberTwoThousandThirtyOneMember" name="StructuredProductDueOctoberTwoThousandThirtyOneMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_StructuredProductFiveMember" name="StructuredProductFiveMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_StructuredProductFourMember" name="StructuredProductFourMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_StructuredProductMember" name="StructuredProductMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_StructuredProductOneMember" name="StructuredProductOneMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_StructuredProductSixMember" name="StructuredProductSixMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_StructuredProductsMember" name="StructuredProductsMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_StructuredProductThreeMember" name="StructuredProductThreeMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_StructuredProductTwoMember" name="StructuredProductTwoMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_SubordinatedNoteDueSeptemberTwoThousandTwentySixMember" name="SubordinatedNoteDueSeptemberTwoThousandTwentySixMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_SupplementalDividendMember" name="SupplementalDividendMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_TangoManagementConsultingLLCMember" name="TangoManagementConsultingLLCMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_TherapeuticsMDIncMember" name="TherapeuticsMDIncMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_TIBCOSoftwareIncMember" name="TIBCOSoftwareIncMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_TradingScreenIncMember" name="TradingScreenIncMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_TransportationMember" name="TransportationMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_TRPAssetsLLCMember" name="TRPAssetsLLCMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_TrustCertificatesOneMember" name="TrustCertificatesOneMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_TrustCertificatesTwoMember" name="TrustCertificatesTwoMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_TwentyTwentyFourNotesMember" name="TwentyTwentyFourNotesMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_TwentyTwentySixNotesMember" name="TwentyTwentySixNotesMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_TwentyTwentyThreeNotesMember" name="TwentyTwentyThreeNotesMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_TwentyTwentyTwoConvertibleNotesMember" name="TwentyTwentyTwoConvertibleNotesMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_TwoThousandTwentyFourNotesMember" name="TwoThousandTwentyFourNotesMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_TwoThousandTwentySixNotesMember" name="TwoThousandTwentySixNotesMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_TwoThousandTwentyThreeAndTwentyFourAndTwentySixNotesMember" name="TwoThousandTwentyThreeAndTwentyFourAndTwentySixNotesMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_TwoThousandTwentyThreeNotesMember" name="TwoThousandTwentyThreeNotesMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_TwoThousandTwentyTwoConvertibleNotesMember" name="TwoThousandTwentyTwoConvertibleNotesMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_USRParentIncMember" name="USRParentIncMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_ValantMedicalSolutionsIncMember" name="ValantMedicalSolutionsIncMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_ValidityIncMember" name="ValidityIncMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_ValueOfInvestmentDeclinesManagementFeeAndIncentiveFeeWillBePayableToAdviserMember" name="ValueOfInvestmentDeclinesManagementFeeAndIncentiveFeeWillBePayableToAdviserMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_VerdadResourcesIntermediateHoldingsLLCMember" name="VerdadResourcesIntermediateHoldingsLLCMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_VoyaCloLtdSeries20183AMember" name="VoyaCloLtdSeries20183AMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_WarrantOneMember" name="WarrantOneMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_WarrantTwoMember" name="WarrantTwoMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_WestMember" name="WestMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_WhiteboxCloILtdSeriesTwoThousandTwentyTwoAMember" name="WhiteboxCloILtdSeriesTwoThousandTwentyTwoAMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_WideOrbitIncMember" name="WideOrbitIncMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_WindRiverCloLtdSeries20142AMember" name="WindRiverCloLtdSeries20142AMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_WindRiverCloLtdSeriesTwoThousandSeventeenOneAMember" name="WindRiverCloLtdSeriesTwoThousandSeventeenOneAMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_WorkwellAcquisitionCoMember" name="WorkwellAcquisitionCoMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_ScheduleOfEarningsPerShareBasicAndDilutedTable" name="ScheduleOfEarningsPerShareBasicAndDilutedTable" type="xbrli:stringItemType" substitutionGroup="xbrldt:hypercubeItem" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_DividendsPolicyTextBlock" name="DividendsPolicyTextBlock" type="dtr-types:textBlockItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
  <xsd:element id="tslx_DividendsTextBlock" name="DividendsTextBlock" type="dtr-types:textBlockItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
  <xsd:element id="tslx_EquityOfferingExpensesPolicyTextBlock" name="EquityOfferingExpensesPolicyTextBlock" type="dtr-types:textBlockItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
  <xsd:element id="tslx_IncomeTaxesIncludingExciseTaxesPolicyTextBlock" name="IncomeTaxesIncludingExciseTaxesPolicyTextBlock" type="dtr-types:textBlockItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
  <xsd:element id="tslx_InterestAndDividendIncomeRecognitionPolicyTextBlock" name="InterestAndDividendIncomeRecognitionPolicyTextBlock" type="dtr-types:textBlockItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
  <xsd:element id="tslx_InvestmentsAtFairValueTextBlock" name="InvestmentsAtFairValueTextBlock" type="dtr-types:textBlockItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
  <xsd:element id="tslx_OffsettingAssetsAndLiabilitiesPolicyTextBlock" name="OffsettingAssetsAndLiabilitiesPolicyTextBlock" type="dtr-types:textBlockItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
  <xsd:element id="tslx_OrganizationPolicyTextBlock" name="OrganizationPolicyTextBlock" type="dtr-types:textBlockItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
  <xsd:element id="tslx_OtherIncomePolicyTextBlock" name="OtherIncomePolicyTextBlock" type="dtr-types:textBlockItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
  <xsd:element id="tslx_ReimbursementOfTransactionRelatedExpensesPolicyTextBlock" name="ReimbursementOfTransactionRelatedExpensesPolicyTextBlock" type="dtr-types:textBlockItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
  <xsd:element id="tslx_ScheduleOfCommitmentsToFundInvestmentsInCurrentPortfolioCompaniesTableTextBlock" name="ScheduleOfCommitmentsToFundInvestmentsInCurrentPortfolioCompaniesTableTextBlock" type="dtr-types:textBlockItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
  <xsd:element id="tslx_ScheduleOfComponentOfCarryingValueOfConvertibleNotesAndInterestRateTableTextBlock" name="ScheduleOfComponentOfCarryingValueOfConvertibleNotesAndInterestRateTableTextBlock" type="dtr-types:textBlockItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
  <xsd:element id="tslx_ScheduleOfComponentsOfInterestExpenseTableTextBlock" name="ScheduleOfComponentsOfInterestExpenseTableTextBlock" type="dtr-types:textBlockItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
  <xsd:element id="tslx_SummaryOfGeographicCompositionOfInvestmentsAtFairValueTableTextBlock" name="SummaryOfGeographicCompositionOfInvestmentsAtFairValueTableTextBlock" type="dtr-types:textBlockItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
  <xsd:element id="tslx_SummaryOfIndustryCompositionOfInvestmentsAtFairValueTableTextBlock" name="SummaryOfIndustryCompositionOfInvestmentsAtFairValueTableTextBlock" type="dtr-types:textBlockItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
  <xsd:element id="tslx_SummaryOfSharesNewlyIssuedToShareholdersWhoHaveNotOptedOutOfDividendReinvestmentPlanTableTextBlock" name="SummaryOfSharesNewlyIssuedToShareholdersWhoHaveNotOptedOutOfDividendReinvestmentPlanTableTextBlock" type="dtr-types:textBlockItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
</xsd:schema>
