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  <xsd:element id="tslx_FairValueOfSecuritiesAsPercentageOfNetAssetsInPercentage" name="FairValueOfSecuritiesAsPercentageOfNetAssetsInPercentage" type="dtr-types:percentItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false"/>
  <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_NetExpense" name="NetExpense" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="debit"/>
  <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_CoupaHoldingsLLCMember" name="CoupaHoldingsLLCMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <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_AgreementTerminationPeriodWithoutPenalty" name="AgreementTerminationPeriodWithoutPenalty" type="xbrli:durationItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
  <xsd:element id="tslx_AccountingStandardsUpdate202206Member" name="AccountingStandardsUpdate202206Member" 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_AsgIiLlcMember" name="AsgIiLlcMember" 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_PartnershipInterestOwnershipPercentage" name="PartnershipInterestOwnershipPercentage" 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_PercentageOfWeightedCumulativeRealizedCapitalGainsLessRealizedCapitalLossesAndUnrealizedCapitalLossesThroughMarch312014HurdleRate" name="PercentageOfWeightedCumulativeRealizedCapitalGainsLessRealizedCapitalLossesAndUnrealizedCapitalLossesThroughMarch312014HurdleRate" type="dtr-types:percentItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
  <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_NetRealizedGainsLossesOnInvestmentsAndForeignCurrencyTranslation" name="NetRealizedGainsLossesOnInvestmentsAndForeignCurrencyTranslation" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="credit"/>
  <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_TRPAssetsLLCMember" name="TRPAssetsLLCMember" 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_IncentiveFeesRealizedAndPayableToAdvisor" name="IncentiveFeesRealizedAndPayableToAdvisor" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="credit"/>
  <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_PerShareMarketValueAtEndPeriod" name="PerShareMarketValueAtEndPeriod" type="dtr-types:perShareItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
  <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_MidwestMember" name="MidwestMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_ConversionOfConvertibleNotes" name="ConversionOfConvertibleNotes" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="credit"/>
  <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_GalileoParentincMember" name="GalileoParentincMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_InterestRateSwaps" name="InterestRateSwaps" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false" xbrli:balance="credit"/>
  <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_NetExpenseForFederalExciseTaxAndOtherTaxes" name="NetExpenseForFederalExciseTaxAndOtherTaxes" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="debit"/>
  <xsd:element id="tslx_DividendsDeclaredDuringThePeriod" name="DividendsDeclaredDuringThePeriod" 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_MezzanineDebtInvestmentsMember" name="MezzanineDebtInvestmentsMember" 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_InterestRateSwapThreeMember" name="InterestRateSwapThreeMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_FairValueOfAnEffectiveHedge" name="FairValueOfAnEffectiveHedge" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false" xbrli:balance="credit"/>
  <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_IndebtednessCouldAdverselyAffectBusinessFinancialConditionsOrResultsOfOperationsMember" name="IndebtednessCouldAdverselyAffectBusinessFinancialConditionsOrResultsOfOperationsMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_IncreaseDecreaseInInterestReceivablePaidInKind" name="IncreaseDecreaseInInterestReceivablePaidInKind" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="debit"/>
  <xsd:element id="tslx_GainLossFormAdjustmentOfPaidInKindInterest" name="GainLossFormAdjustmentOfPaidInKindInterest" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="credit"/>
  <xsd:element id="tslx_BtrsHoldingIncMember" name="BtrsHoldingIncMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_InvestmentsInAndAdvancesToAffiliatesAtFairValueNetChangeInUnrealizedGainLoss" name="InvestmentsInAndAdvancesToAffiliatesAtFairValueNetChangeInUnrealizedGainLoss" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="credit"/>
  <xsd:element id="tslx_InvestmentsInAndAdvancesToAffiliatesAtFairValueRealizedGainLoss" name="InvestmentsInAndAdvancesToAffiliatesAtFairValueRealizedGainLoss" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="credit"/>
  <xsd:element id="tslx_AssetCoveragePercentage" name="AssetCoveragePercentage" type="dtr-types:percentItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false"/>
  <xsd:element id="tslx_TwentyTwentyEightNotesMember" name="TwentyTwentyEightNotesMember" 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_PercentageOfAllPreIncentiveFeeNetInvestmentIncomeAfterCatchUpAchieved" name="PercentageOfAllPreIncentiveFeeNetInvestmentIncomeAfterCatchUpAchieved" type="dtr-types:percentItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
  <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_ThreeMonthLiborMember" name="ThreeMonthLiborMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_IncreaseDecreaseInManagementFeesPayableToAffiliate" name="IncreaseDecreaseInManagementFeesPayableToAffiliate" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="debit"/>
  <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_OriginalIssueDiscountNetOfAccretion" name="OriginalIssueDiscountNetOfAccretion" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false" xbrli:balance="credit"/>
  <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_InterestRateSwapTwoMember" name="InterestRateSwapTwoMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <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_NeuintelLLCMember" name="NeuintelLLCMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_OutsystemsLuxcoMember" name="OutsystemsLuxcoMember" 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_ScheduleOfEarningsPerShareBasicAndDilutedTable" name="ScheduleOfEarningsPerShareBasicAndDilutedTable" type="xbrli:stringItemType" substitutionGroup="xbrldt:hypercubeItem" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_FairValueOfSecuritiesAsPercentageOfNetAssetsAmount" name="FairValueOfSecuritiesAsPercentageOfNetAssetsAmount" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false" xbrli:balance="debit"/>
  <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_BlueSnapIncMember" name="BlueSnapIncMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_LineOfCreditFacilityExtendedDate" name="LineOfCreditFacilityExtendedDate" type="xbrli:dateItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
  <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_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetPaidInKindInterest" name="FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetPaidInKindInterest" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="credit"/>
  <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_RevolvingCreditFacilityMaturityOnJuneTwelveTwoThousandAndTwentyEightMember" name="RevolvingCreditFacilityMaturityOnJuneTwelveTwoThousandAndTwentyEightMember" 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_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetTransfersWithinLevel3" name="FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetTransfersWithinLevel3" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="debit"/>
  <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_ProceedsFromInvestmentsNet" name="ProceedsFromInvestmentsNet" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="debit"/>
  <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_TotalReturnBasedOnNetAssetValue" name="TotalReturnBasedOnNetAssetValue" type="dtr-types:percentItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false"/>
  <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_NetwrixCorpMember" name="NetwrixCorpMember" 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_InterestRateSwapTenMember" name="InterestRateSwapTenMember" 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_ArrowbuyerIncMember" name="ArrowbuyerIncMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_DividendsPayableDateOfSharesIssuedDayMonthAndYear" name="DividendsPayableDateOfSharesIssuedDayMonthAndYear" type="xbrli:dateItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
  <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_SignificantAccountingPoliciesTable" name="SignificantAccountingPoliciesTable" type="xbrli:stringItemType" substitutionGroup="xbrldt:hypercubeItem" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <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_WranglerTopcoLlcMember" name="WranglerTopcoLlcMember" 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_MinimumPercentageOfInvestmentCompanyTaxableIncomeDistributeToStockholdersInEachTaxableYearToQualifyAsRIC" name="MinimumPercentageOfInvestmentCompanyTaxableIncomeDistributeToStockholdersInEachTaxableYearToQualifyAsRIC" type="dtr-types:percentItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
  <xsd:element id="tslx_PercentageOfManagementFeeInExcessOfQuarterRateOnGrossAssets" name="PercentageOfManagementFeeInExcessOfQuarterRateOnGrossAssets" type="dtr-types:percentItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
  <xsd:element id="tslx_StructuredCreditInvestments" name="StructuredCreditInvestments" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false" xbrli:balance="debit"/>
  <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_MarketingServicesMember" name="MarketingServicesMember" 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_SummaryOfSharesNewlyIssuedToShareholdersWhoHaveNotOptedOutOfDividendReinvestmentPlanTableTextBlock" name="SummaryOfSharesNewlyIssuedToShareholdersWhoHaveNotOptedOutOfDividendReinvestmentPlanTableTextBlock" type="dtr-types:textBlockItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
  <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_ExtraHopNetworksIncMember" name="ExtraHopNetworksIncMember" 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_PercentageOfManagementFeeCalculatedOnGrossAssets" name="PercentageOfManagementFeeCalculatedOnGrossAssets" type="dtr-types:percentItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
  <xsd:element id="tslx_CurrentMarketPricePerSharePercentage" name="CurrentMarketPricePerSharePercentage" type="dtr-types:percentItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
  <xsd:element id="tslx_BanyanSoftwareHoldingsLlcMember" name="BanyanSoftwareHoldingsLlcMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_TwoThousandTwentyThreeTwentyFourTwentySixAndTwentyEightNotesMember" name="TwoThousandTwentyThreeTwentyFourTwentySixAndTwentyEightNotesMember" 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_UpfrontPaymentsReceiptsInDerivativeAssetsAndLiabilities" name="UpfrontPaymentsReceiptsInDerivativeAssetsAndLiabilities" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="credit"/>
  <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_CordanceOperationsLlcMember" name="CordanceOperationsLlcMember" 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_RepaymentsOnInvestments" name="RepaymentsOnInvestments" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="credit"/>
  <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_InterestRateSwapTwelveMember" name="InterestRateSwapTwelveMember" 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_PercentageOfAllRemainingPreIncentiveFeeNetInvestmentIncomeQuarterly" name="PercentageOfAllRemainingPreIncentiveFeeNetInvestmentIncomeQuarterly" type="dtr-types:percentItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
  <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_InvestmentCompanySettlementOfConvertibleNotesPerShare" name="InvestmentCompanySettlementOfConvertibleNotesPerShare" type="dtr-types:perShareItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
  <xsd:element id="tslx_AvalaraIncMember" name="AvalaraIncMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_IncentiveFeesAccruedRelatedToExpenseReversalCapitalGainsFees" name="IncentiveFeesAccruedRelatedToExpenseReversalCapitalGainsFees" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="debit"/>
  <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_CommunicationsMember" name="CommunicationsMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_IncentiveFeesOnNetCapitalGains" name="IncentiveFeesOnNetCapitalGains" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="debit"/>
  <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_EarningsPerShareBasicAndDilutedLineItems" name="EarningsPerShareBasicAndDilutedLineItems" type="xbrli:stringItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_LaramieEnergyLLCMember" name="LaramieEnergyLLCMember" type="dtr-types:domainItemType" 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_ProceedsFromSettlementsOfInterestRateSwapsExcludingUpfrontFees" name="ProceedsFromSettlementsOfInterestRateSwapsExcludingUpfrontFees" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="debit"/>
  <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_IntelePeerHoldingsIncMember" name="IntelePeerHoldingsIncMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_DividendsDeclaredFromNetInvestmentIncomePerShare" name="DividendsDeclaredFromNetInvestmentIncomePerShare" type="dtr-types:perShareItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
  <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_TransportationMember" name="TransportationMember" 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_EdgeBidcoBVMember" name="EdgeBidcoBVMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_IncentiveFeesOnNetCapitalGainsAccruedToAffiliate" name="IncentiveFeesOnNetCapitalGainsAccruedToAffiliate" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false" xbrli:balance="credit"/>
  <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_PaidInKindInterestIncome" name="PaidInKindInterestIncome" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="credit"/>
  <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_RapidDataGmbhUnternehmensberatungMember" name="RapidDataGmbhUnternehmensberatungMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_HirevueIncMember" name="HirevueIncMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_AdditionalAggregatePrincipalAmount" name="AdditionalAggregatePrincipalAmount" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false" xbrli:balance="credit"/>
  <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_FutureRealizedCapitalGainsPriorToAprilFirstTwoThousandFourteenMember" name="FutureRealizedCapitalGainsPriorToAprilFirstTwoThousandFourteenMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <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_TwentyTwentySixNotesMember" name="TwentyTwentySixNotesMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <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_ValueOfInvestmentDeclinesManagementFeeAndIncentiveFeeWillBePayableToAdviserMember" name="ValueOfInvestmentDeclinesManagementFeeAndIncentiveFeeWillBePayableToAdviserMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_InvestmentsInAndAdvancesToAffiliatesOtherIncome" name="InvestmentsInAndAdvancesToAffiliatesOtherIncome" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="credit"/>
  <xsd:element id="tslx_InvestmentsOwnedEstimatedCostBasis" name="InvestmentsOwnedEstimatedCostBasis" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false" xbrli:balance="debit"/>
  <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_AlaskaBidcoOyMember" name="AlaskaBidcoOyMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_PaymentsForSettlementsOfInterestRateSwapsExcludingUpfrontFees" name="PaymentsForSettlementsOfInterestRateSwapsExcludingUpfrontFees" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="credit"/>
  <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_AbilityToRaiseAdditionalCapitalDueToRegulationGovernanceOnBdcMember" name="AbilityToRaiseAdditionalCapitalDueToRegulationGovernanceOnBdcMember" 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_BearOpCoLLCMember" name="BearOpCoLLCMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_NetRealizedGainsLossesOnForeignCurrencyTransactions" name="NetRealizedGainsLossesOnForeignCurrencyTransactions" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="credit"/>
  <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_CarlstarGroupLLCMember" name="CarlstarGroupLLCMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_IncentiveFeesOnNetInvestmentIncomePayableToAffiliate" name="IncentiveFeesOnNetInvestmentIncomePayableToAffiliate" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false" xbrli:balance="credit"/>
  <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_TwoThousandTwentyThreeAndTwentyFourAndTwentySixNotesMember" name="TwoThousandTwentyThreeAndTwentyFourAndTwentySixNotesMember" 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_BctoBluebillBuyerIncMember" name="BctoBluebillBuyerIncMember" 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_EquityOfferingExpensesPolicyTextBlock" name="EquityOfferingExpensesPolicyTextBlock" type="dtr-types:textBlockItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
  <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_PercentageOfNonQualifyingAssets" name="PercentageOfNonQualifyingAssets" type="dtr-types:percentItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
  <xsd:element id="tslx_InvestmentCompanyIssuanceAndRepurchasePerShare" name="InvestmentCompanyIssuanceAndRepurchasePerShare" type="dtr-types:perShareItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
  <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_TwoThousandTwentySixNotesMember" name="TwoThousandTwentySixNotesMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_OtherPayablesToAffiliate" name="OtherPayablesToAffiliate" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false" xbrli:balance="credit"/>
  <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_ManufacturingMember" name="ManufacturingMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_LineOfCreditFacilityStatedMaturityDate" name="LineOfCreditFacilityStatedMaturityDate" type="xbrli:dateItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
  <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_ReliaQuestHoldingsLLCMember" name="ReliaQuestHoldingsLLCMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_InvestmentsInAndAdvancesToAffiliatesInterestIncome" name="InvestmentsInAndAdvancesToAffiliatesInterestIncome" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="credit"/>
  <xsd:element id="tslx_DebtConversionPrincipalAmount" name="DebtConversionPrincipalAmount" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="credit"/>
  <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_ElysianFincoLtdMember" name="ElysianFincoLtdMember" 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_IncreaseDecreaseInIncentiveFeesOnNetInvestmentIncomePayableToAffiliate" name="IncreaseDecreaseInIncentiveFeesOnNetInvestmentIncomePayableToAffiliate" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="credit"/>
  <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_InterestRateSwapFourMember" name="InterestRateSwapFourMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <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_TotalReturnBasedOnMarketValueWithReinvestmentOfDividends" name="TotalReturnBasedOnMarketValueWithReinvestmentOfDividends" type="dtr-types:percentItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false"/>
  <xsd:element id="tslx_StructuredCreditInvestmentsMember" name="StructuredCreditInvestmentsMember" 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_UnRealizedInvestmentGainsLossesAbstract" name="UnRealizedInvestmentGainsLossesAbstract" type="xbrli:stringItemType" 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_NetChangeInUnrealizedGainsLossesOnInvestmentsAndForeignCurrencyTranslation" name="NetChangeInUnrealizedGainsLossesOnInvestmentsAndForeignCurrencyTranslation" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="credit"/>
  <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_PercentageOfCapitalGainsFromApril12024HurdleRate" name="PercentageOfCapitalGainsFromApril12024HurdleRate" type="dtr-types:percentItemType" 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_OtherMember" name="OtherMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" 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_PercentageOfPreIncentiveFeeNetInvestmentIncomeAnnualizedAfterCatchUpAchieved" name="PercentageOfPreIncentiveFeeNetInvestmentIncomeAnnualizedAfterCatchUpAchieved" 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_RevolvingCreditFacilityMaturityOnJanuary312025Member" name="RevolvingCreditFacilityMaturityOnJanuary312025Member" 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_InterestRateSwapElevenMember" name="InterestRateSwapElevenMember" 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_PingIdentityCorporationMember" name="PingIdentityCorporationMember" 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_AxonifyIncMember" name="AxonifyIncMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="tslx_PercentageOfExcessCatchUpProvisionForPreIncentiveFeeNetInvestmentIncome" name="PercentageOfExcessCatchUpProvisionForPreIncentiveFeeNetInvestmentIncome" type="dtr-types:percentItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
  <xsd:element id="tslx_EducationMember" name="EducationMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
</xsd:schema>
