<?xml version="1.0"?>
<edgarSubmission>

    <schemaVersion>X0708</schemaVersion>

    <submissionType>D/A</submissionType>

    <testOrLive>LIVE</testOrLive>

    <primaryIssuer>
        <cik>0002055376</cik>
        <entityName>True Green Capital Fund V-B, L.P.</entityName>
        <issuerAddress>
            <street1>315 POST ROAD WEST</street1>
            <city>WESTPORT</city>
            <stateOrCountry>CT</stateOrCountry>
            <stateOrCountryDescription>CONNECTICUT</stateOrCountryDescription>
            <zipCode>06880</zipCode>
        </issuerAddress>
        <issuerPhoneNumber>203-557-6227</issuerPhoneNumber>
        <jurisdictionOfInc>DELAWARE</jurisdictionOfInc>
        <issuerPreviousNameList>
            <value>None</value>
        </issuerPreviousNameList>
        <edgarPreviousNameList>
            <value>None</value>
        </edgarPreviousNameList>
        <entityType>Limited Partnership</entityType>
        <yearOfInc>
            <withinFiveYears>true</withinFiveYears>
            <value>2024</value>
        </yearOfInc>
    </primaryIssuer>

    <relatedPersonsList>
        <relatedPersonInfo>
            <relatedPersonName>
                <firstName>n/a</firstName>
                <lastName>TGC Asset Management V LLC</lastName>
            </relatedPersonName>
            <relatedPersonAddress>
                <street1>315 Post Road West</street1>
                <city>Westport</city>
                <stateOrCountry>CT</stateOrCountry>
                <stateOrCountryDescription>CONNECTICUT</stateOrCountryDescription>
                <zipCode>06880</zipCode>
            </relatedPersonAddress>
            <relatedPersonRelationshipList>
                <relationship>Executive Officer</relationship>
                <relationship>Promoter</relationship>
            </relatedPersonRelationshipList>
            <relationshipClarification>The General Partner of the Issuer</relationshipClarification>
        </relatedPersonInfo>
        <relatedPersonInfo>
            <relatedPersonName>
                <firstName>n/a</firstName>
                <lastName>True Green Capital Management LLC</lastName>
            </relatedPersonName>
            <relatedPersonAddress>
                <street1>315 Post Road West</street1>
                <city>Westport</city>
                <stateOrCountry>CT</stateOrCountry>
                <stateOrCountryDescription>CONNECTICUT</stateOrCountryDescription>
                <zipCode>06880</zipCode>
            </relatedPersonAddress>
            <relatedPersonRelationshipList>
                <relationship>Promoter</relationship>
            </relatedPersonRelationshipList>
            <relationshipClarification>The Investment Manager of the Issuer</relationshipClarification>
        </relatedPersonInfo>
        <relatedPersonInfo>
            <relatedPersonName>
                <firstName>Panagiotis</firstName>
                <lastName>Ninios</lastName>
            </relatedPersonName>
            <relatedPersonAddress>
                <street1>315 Post Road West</street1>
                <city>Westport</city>
                <stateOrCountry>CT</stateOrCountry>
                <stateOrCountryDescription>CONNECTICUT</stateOrCountryDescription>
                <zipCode>72201</zipCode>
            </relatedPersonAddress>
            <relatedPersonRelationshipList>
                <relationship>Executive Officer</relationship>
                <relationship>Promoter</relationship>
            </relatedPersonRelationshipList>
            <relationshipClarification>Dr. Ninios is a member of the Board Of Managers of the General Partner of the Issuer. He is also the co-managing partner of the Investment Manager.</relationshipClarification>
        </relatedPersonInfo>
        <relatedPersonInfo>
            <relatedPersonName>
                <firstName>Bruce</firstName>
                <lastName>Wiegand</lastName>
            </relatedPersonName>
            <relatedPersonAddress>
                <street1>315 Post Road West</street1>
                <city>Westport</city>
                <stateOrCountry>CT</stateOrCountry>
                <stateOrCountryDescription>CONNECTICUT</stateOrCountryDescription>
                <zipCode>72201</zipCode>
            </relatedPersonAddress>
            <relatedPersonRelationshipList>
                <relationship>Executive Officer</relationship>
                <relationship>Promoter</relationship>
            </relatedPersonRelationshipList>
            <relationshipClarification>Mr. Wiegand is a member of the Board of Managers of the General Partner of the Issuer. He is also the co-managing partner of the Investment Manager.</relationshipClarification>
        </relatedPersonInfo>
    </relatedPersonsList>

    <offeringData>
        <industryGroup>
            <industryGroupType>Pooled Investment Fund</industryGroupType>
            <investmentFundInfo>
                <investmentFundType>Other Investment Fund</investmentFundType>
                <is40Act>false</is40Act>
            </investmentFundInfo>
        </industryGroup>
        <issuerSize>
            <aggregateNetAssetValueRange>Decline to Disclose</aggregateNetAssetValueRange>
        </issuerSize>
        <federalExemptionsExclusions>
            <item>06b</item>
            <item>3C</item>
            <item>3C.7</item>
        </federalExemptionsExclusions>
        <typeOfFiling>
            <newOrAmendment>
                <isAmendment>true</isAmendment>
                <previousAccessionNumber>0000929638-25-001503</previousAccessionNumber>
            </newOrAmendment>
            <dateOfFirstSale>
                <value>2025-04-07</value>
            </dateOfFirstSale>
        </typeOfFiling>
        <durationOfOffering>
            <moreThanOneYear>true</moreThanOneYear>
        </durationOfOffering>
        <typesOfSecuritiesOffered>
            <isPooledInvestmentFundType>true</isPooledInvestmentFundType>
            <isOtherType>true</isOtherType>
            <descriptionOfOtherType>Limited Partnership Interests. The minimum capital commitment of $10,000,000 may be waived by the General Partner.</descriptionOfOtherType>
        </typesOfSecuritiesOffered>
        <businessCombinationTransaction>
            <isBusinessCombinationTransaction>false</isBusinessCombinationTransaction>
            <clarificationOfResponse></clarificationOfResponse>
        </businessCombinationTransaction>
        <minimumInvestmentAccepted>0</minimumInvestmentAccepted>
        <salesCompensationList>
            <recipient>
                <recipientName>None</recipientName>
                <recipientCRDNumber>None</recipientCRDNumber>
                <associatedBDName>Strategic Marketing Solutions Ltd., LLC</associatedBDName>
                <associatedBDCRDNumber>145577</associatedBDCRDNumber>
                <recipientAddress>
                    <street1>2302B Bridgeway</street1>
                    <city>Sausalito</city>
                    <stateOrCountry>CA</stateOrCountry>
                    <stateOrCountryDescription>CALIFORNIA</stateOrCountryDescription>
                    <zipCode>94965</zipCode>
                </recipientAddress>
                <statesOfSolicitationList>
                    <state>CA</state>
                    <description>CALIFORNIA</description>
                    <state>CT</state>
                    <description>CONNECTICUT</description>
                    <state>FL</state>
                    <description>FLORIDA</description>
                    <state>MA</state>
                    <description>MASSACHUSETTS</description>
                    <state>MO</state>
                    <description>MISSOURI</description>
                    <state>VA</state>
                    <description>VIRGINIA</description>
                </statesOfSolicitationList>
                <foreignSolicitation>false</foreignSolicitation>
            </recipient>
        </salesCompensationList>
        <offeringSalesAmounts>
            <totalOfferingAmount>Indefinite</totalOfferingAmount>
            <totalAmountSold>100000000</totalAmountSold>
            <totalRemaining>Indefinite</totalRemaining>
            <clarificationOfResponse>There is a $1 billion cap across True Green Capital Fund V, L.P., True Green Capital Fund V-A, L.P. and True Green Capital Fund V-B, L.P., which can be waived with the written consent by a majority in interest of the limited partners.</clarificationOfResponse>
        </offeringSalesAmounts>
        <investors>
            <hasNonAccreditedInvestors>false</hasNonAccreditedInvestors>
            <totalNumberAlreadyInvested>1</totalNumberAlreadyInvested>
        </investors>
        <salesCommissionsFindersFees>
            <salesCommissions>
                <dollarAmount>0</dollarAmount>
            </salesCommissions>
            <findersFees>
                <dollarAmount>0</dollarAmount>
            </findersFees>
            <clarificationOfResponse>The persons named in Item 12 will receive a commission based on a percentage of the sales of the Issuer's securities.</clarificationOfResponse>
        </salesCommissionsFindersFees>
        <useOfProceeds>
            <grossProceedsUsed>
                <dollarAmount>0</dollarAmount>
            </grossProceedsUsed>
            <clarificationOfResponse>Certain persons named in Item 3 or affiliates thereof may receive payments deemed to be made from the proceeds of the offering, including management fees. The amounts of such fees cannot be estimated at this time.</clarificationOfResponse>
        </useOfProceeds>
        <signatureBlock>
            <authorizedRepresentative>false</authorizedRepresentative>
            <signature>
                <issuerName>True Green Capital Fund V-B, L.P.</issuerName>
                <signatureName>/s/ Panagiotis Ninios</signatureName>
                <nameOfSigner>Panagiotis Ninios</nameOfSigner>
                <signatureTitle>Manager of the General Partner of the Issuer</signatureTitle>
                <signatureDate>2026-04-06</signatureDate>
            </signature>
        </signatureBlock>
    </offeringData>
</edgarSubmission>
