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    <schemaVersion>X0708</schemaVersion>

    <submissionType>D</submissionType>

    <testOrLive>LIVE</testOrLive>

    <primaryIssuer>
        <cik>0002011982</cik>
        <entityName>GTCR CAPITAL SOLUTIONS FEEDER B LP</entityName>
        <issuerAddress>
            <street1>300 NORTH LASALLE STREET, SUITE 5600</street1>
            <city>CHICAGO</city>
            <stateOrCountry>IL</stateOrCountry>
            <stateOrCountryDescription>ILLINOIS</stateOrCountryDescription>
            <zipCode>60654</zipCode>
        </issuerAddress>
        <issuerPhoneNumber>(312) 382-2200</issuerPhoneNumber>
        <jurisdictionOfInc>DELAWARE</jurisdictionOfInc>
        <edgarPreviousNameList>
            <previousName>GTCR CAPITAL SOLUTIONS FUND B LP</previousName>
        </edgarPreviousNameList>
        <entityType>Limited Partnership</entityType>
        <yearOfInc>
            <withinFiveYears>true</withinFiveYears>
            <value>2024</value>
        </yearOfInc>
    </primaryIssuer>

    <relatedPersonsList>
        <relatedPersonInfo>
            <relatedPersonName>
                <firstName>MARK</firstName>
                <middleName>M.</middleName>
                <lastName>ANDERSON</lastName>
            </relatedPersonName>
            <relatedPersonAddress>
                <street1>300 NORTH LASALLE STREET, SUITE 5600</street1>
                <city>CHICAGO</city>
                <stateOrCountry>IL</stateOrCountry>
                <stateOrCountryDescription>ILLINOIS</stateOrCountryDescription>
                <zipCode>60654</zipCode>
            </relatedPersonAddress>
            <relatedPersonRelationshipList>
                <relationship>Executive Officer</relationship>
                <relationship>Promoter</relationship>
            </relatedPersonRelationshipList>
            <relationshipClarification></relationshipClarification>
        </relatedPersonInfo>
        <relatedPersonInfo>
            <relatedPersonName>
                <firstName>AARON</firstName>
                <middleName>D.</middleName>
                <lastName>COHEN</lastName>
            </relatedPersonName>
            <relatedPersonAddress>
                <street1>300 NORTH LASALLE STREET, SUITE 5600</street1>
                <city>CHICAGO</city>
                <stateOrCountry>IL</stateOrCountry>
                <stateOrCountryDescription>ILLINOIS</stateOrCountryDescription>
                <zipCode>60654</zipCode>
            </relatedPersonAddress>
            <relatedPersonRelationshipList>
                <relationship>Executive Officer</relationship>
                <relationship>Promoter</relationship>
            </relatedPersonRelationshipList>
            <relationshipClarification></relationshipClarification>
        </relatedPersonInfo>
        <relatedPersonInfo>
            <relatedPersonName>
                <firstName>SEAN</firstName>
                <middleName>L.</middleName>
                <lastName>CUNNINGHAM</lastName>
            </relatedPersonName>
            <relatedPersonAddress>
                <street1>300 NORTH LASALLE STREET, SUITE 5600</street1>
                <city>CHICAGO</city>
                <stateOrCountry>IL</stateOrCountry>
                <stateOrCountryDescription>ILLINOIS</stateOrCountryDescription>
                <zipCode>60654</zipCode>
            </relatedPersonAddress>
            <relatedPersonRelationshipList>
                <relationship>Executive Officer</relationship>
                <relationship>Promoter</relationship>
            </relatedPersonRelationshipList>
            <relationshipClarification></relationshipClarification>
        </relatedPersonInfo>
        <relatedPersonInfo>
            <relatedPersonName>
                <firstName>DAVID</firstName>
                <middleName>A.</middleName>
                <lastName>DONNINI</lastName>
            </relatedPersonName>
            <relatedPersonAddress>
                <street1>300 NORTH LASALLE STREET, SUITE 5600</street1>
                <city>CHICAGO</city>
                <stateOrCountry>IL</stateOrCountry>
                <stateOrCountryDescription>ILLINOIS</stateOrCountryDescription>
                <zipCode>60654</zipCode>
            </relatedPersonAddress>
            <relatedPersonRelationshipList>
                <relationship>Executive Officer</relationship>
                <relationship>Promoter</relationship>
            </relatedPersonRelationshipList>
            <relationshipClarification></relationshipClarification>
        </relatedPersonInfo>
        <relatedPersonInfo>
            <relatedPersonName>
                <firstName>CONSTANTINE</firstName>
                <middleName>S.</middleName>
                <lastName>MIHAS</lastName>
            </relatedPersonName>
            <relatedPersonAddress>
                <street1>300 NORTH LASALLE STREET, SUITE 5600</street1>
                <city>CHICAGO</city>
                <stateOrCountry>IL</stateOrCountry>
                <stateOrCountryDescription>ILLINOIS</stateOrCountryDescription>
                <zipCode>60654</zipCode>
            </relatedPersonAddress>
            <relatedPersonRelationshipList>
                <relationship>Executive Officer</relationship>
                <relationship>Promoter</relationship>
            </relatedPersonRelationshipList>
            <relationshipClarification></relationshipClarification>
        </relatedPersonInfo>
        <relatedPersonInfo>
            <relatedPersonName>
                <firstName>COLLIN</firstName>
                <middleName>E.</middleName>
                <lastName>ROCHE</lastName>
            </relatedPersonName>
            <relatedPersonAddress>
                <street1>300 NORTH LASALLE STREET, SUITE 5600</street1>
                <city>CHICAGO</city>
                <stateOrCountry>IL</stateOrCountry>
                <stateOrCountryDescription>ILLINOIS</stateOrCountryDescription>
                <zipCode>60654</zipCode>
            </relatedPersonAddress>
            <relatedPersonRelationshipList>
                <relationship>Executive Officer</relationship>
                <relationship>Promoter</relationship>
            </relatedPersonRelationshipList>
            <relationshipClarification></relationshipClarification>
        </relatedPersonInfo>
        <relatedPersonInfo>
            <relatedPersonName>
                <firstName>ANNA MAY</firstName>
                <middleName>L.</middleName>
                <lastName>TRALA</lastName>
            </relatedPersonName>
            <relatedPersonAddress>
                <street1>300 NORTH LASALLE STREET, SUITE 5600</street1>
                <city>CHICAGO</city>
                <stateOrCountry>IL</stateOrCountry>
                <stateOrCountryDescription>ILLINOIS</stateOrCountryDescription>
                <zipCode>60654</zipCode>
            </relatedPersonAddress>
            <relatedPersonRelationshipList>
                <relationship>Executive Officer</relationship>
                <relationship>Promoter</relationship>
            </relatedPersonRelationshipList>
            <relationshipClarification></relationshipClarification>
        </relatedPersonInfo>
        <relatedPersonInfo>
            <relatedPersonName>
                <firstName>JEFFREY</firstName>
                <middleName>S.</middleName>
                <lastName>WRIGHT</lastName>
            </relatedPersonName>
            <relatedPersonAddress>
                <street1>300 NORTH LASALLE STREET, SUITE 5600</street1>
                <city>CHICAGO</city>
                <stateOrCountry>IL</stateOrCountry>
                <stateOrCountryDescription>ILLINOIS</stateOrCountryDescription>
                <zipCode>60654</zipCode>
            </relatedPersonAddress>
            <relatedPersonRelationshipList>
                <relationship>Executive Officer</relationship>
                <relationship>Promoter</relationship>
            </relatedPersonRelationshipList>
            <relationshipClarification></relationshipClarification>
        </relatedPersonInfo>
    </relatedPersonsList>

    <offeringData>
        <industryGroup>
            <industryGroupType>Pooled Investment Fund</industryGroupType>
            <investmentFundInfo>
                <investmentFundType>Private Equity Fund</investmentFundType>
                <is40Act>false</is40Act>
            </investmentFundInfo>
        </industryGroup>
        <issuerSize>
            <revenueRange>Decline to Disclose</revenueRange>
        </issuerSize>
        <federalExemptionsExclusions>
            <item>06b</item>
            <item>3C</item>
            <item>3C.7</item>
        </federalExemptionsExclusions>
        <typeOfFiling>
            <newOrAmendment>
                <isAmendment>false</isAmendment>
            </newOrAmendment>
            <dateOfFirstSale>
                <yetToOccur>true</yetToOccur>
            </dateOfFirstSale>
        </typeOfFiling>
        <durationOfOffering>
            <moreThanOneYear>false</moreThanOneYear>
        </durationOfOffering>
        <typesOfSecuritiesOffered>
            <isEquityType>true</isEquityType>
            <isPooledInvestmentFundType>true</isPooledInvestmentFundType>
        </typesOfSecuritiesOffered>
        <businessCombinationTransaction>
            <isBusinessCombinationTransaction>false</isBusinessCombinationTransaction>
            <clarificationOfResponse></clarificationOfResponse>
        </businessCombinationTransaction>
        <minimumInvestmentAccepted>0</minimumInvestmentAccepted>
        <salesCompensationList></salesCompensationList>
        <offeringSalesAmounts>
            <totalOfferingAmount>Indefinite</totalOfferingAmount>
            <totalAmountSold>0</totalAmountSold>
            <totalRemaining>Indefinite</totalRemaining>
            <clarificationOfResponse></clarificationOfResponse>
        </offeringSalesAmounts>
        <investors>
            <hasNonAccreditedInvestors>false</hasNonAccreditedInvestors>
            <totalNumberAlreadyInvested>0</totalNumberAlreadyInvested>
        </investors>
        <salesCommissionsFindersFees>
            <salesCommissions>
                <dollarAmount>0</dollarAmount>
                <isEstimate>true</isEstimate>
            </salesCommissions>
            <findersFees>
                <dollarAmount>0</dollarAmount>
                <isEstimate>true</isEstimate>
            </findersFees>
            <clarificationOfResponse>Such fees, if any, will only be paid upon the sale of interests to certain non-U.S. investors and such amounts will not be finalized until the final closing of the offering.</clarificationOfResponse>
        </salesCommissionsFindersFees>
        <useOfProceeds>
            <grossProceedsUsed>
                <dollarAmount>0</dollarAmount>
                <isEstimate>true</isEstimate>
            </grossProceedsUsed>
            <clarificationOfResponse>The general partner is entitled to a performance allocation. The investment manager is entitled to a management fee. The performance allocation and management fee are fully discussed in the Issuer's confidential offering materials.</clarificationOfResponse>
        </useOfProceeds>
        <signatureBlock>
            <authorizedRepresentative>false</authorizedRepresentative>
            <signature>
                <issuerName>GTCR CAPITAL SOLUTIONS FEEDER B LP</issuerName>
                <signatureName>/S/ COLLIN E. ROCHE</signatureName>
                <nameOfSigner>COLLIN E. ROCHE</nameOfSigner>
                <signatureTitle>MANAGER OF THE GP OF THE GP OF THE ISSUER</signatureTitle>
                <signatureDate>2024-12-27</signatureDate>
            </signature>
        </signatureBlock>
    </offeringData>
</edgarSubmission>
