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

    <schemaVersion>X0708</schemaVersion>

    <submissionType>D</submissionType>

    <testOrLive>LIVE</testOrLive>

    <primaryIssuer>
        <cik>0001889664</cik>
        <entityName>AIOF II Vanir Co-Invest B, L.P.</entityName>
        <issuerAddress>
            <street1>ONE MANHATTANVILLE ROAD</street1>
            <street2>SUITE 201</street2>
            <city>PURCHASE</city>
            <stateOrCountry>NY</stateOrCountry>
            <stateOrCountryDescription>NEW YORK</stateOrCountryDescription>
            <zipCode>10577</zipCode>
        </issuerAddress>
        <issuerPhoneNumber>914-694-8000</issuerPhoneNumber>
        <jurisdictionOfInc>DELAWARE</jurisdictionOfInc>
        <issuerPreviousNameList>
            <value>None</value>
        </issuerPreviousNameList>
        <edgarPreviousNameList>
            <value>None</value>
        </edgarPreviousNameList>
        <entityType>Limited Partnership</entityType>
        <yearOfInc>
            <withinFiveYears>true</withinFiveYears>
            <value>2021</value>
        </yearOfInc>
    </primaryIssuer>

    <relatedPersonsList>
        <relatedPersonInfo>
            <relatedPersonName>
                <firstName>James</firstName>
                <lastName>Elworth</lastName>
            </relatedPersonName>
            <relatedPersonAddress>
                <street1>9 West 57th Street</street1>
                <street2>43rd Floor</street2>
                <city>New York</city>
                <stateOrCountry>NY</stateOrCountry>
                <stateOrCountryDescription>NEW YORK</stateOrCountryDescription>
                <zipCode>10019</zipCode>
            </relatedPersonAddress>
            <relatedPersonRelationshipList>
                <relationship>Executive Officer</relationship>
            </relatedPersonRelationshipList>
            <relationshipClarification>Executive Officer of the general partner of the Issuer</relationshipClarification>
        </relatedPersonInfo>
        <relatedPersonInfo>
            <relatedPersonName>
                <firstName>James</firstName>
                <middleName>C.</middleName>
                <lastName>Zelter</lastName>
            </relatedPersonName>
            <relatedPersonAddress>
                <street1>9 West 57th Street</street1>
                <city>New York</city>
                <stateOrCountry>NY</stateOrCountry>
                <stateOrCountryDescription>NEW YORK</stateOrCountryDescription>
                <zipCode>10019</zipCode>
            </relatedPersonAddress>
            <relatedPersonRelationshipList>
                <relationship>Executive Officer</relationship>
            </relatedPersonRelationshipList>
            <relationshipClarification>Executive Officer of the GP of the Issuer</relationshipClarification>
        </relatedPersonInfo>
        <relatedPersonInfo>
            <relatedPersonName>
                <firstName>Marc</firstName>
                <middleName>J.</middleName>
                <lastName>Rowan</lastName>
            </relatedPersonName>
            <relatedPersonAddress>
                <street1>9 West 57th Street</street1>
                <city>New York</city>
                <stateOrCountry>NY</stateOrCountry>
                <stateOrCountryDescription>NEW YORK</stateOrCountryDescription>
                <zipCode>10019</zipCode>
            </relatedPersonAddress>
            <relatedPersonRelationshipList>
                <relationship>Executive Officer</relationship>
            </relatedPersonRelationshipList>
            <relationshipClarification>Executive Officer of the GP of the Issuer</relationshipClarification>
        </relatedPersonInfo>
        <relatedPersonInfo>
            <relatedPersonName>
                <firstName>Scott</firstName>
                <lastName>Kleinman</lastName>
            </relatedPersonName>
            <relatedPersonAddress>
                <street1>9 West 57th Street</street1>
                <city>New York</city>
                <stateOrCountry>NY</stateOrCountry>
                <stateOrCountryDescription>NEW YORK</stateOrCountryDescription>
                <zipCode>10019</zipCode>
            </relatedPersonAddress>
            <relatedPersonRelationshipList>
                <relationship>Executive Officer</relationship>
            </relatedPersonRelationshipList>
            <relationshipClarification>Executive Officer of the GP of the Issuer</relationshipClarification>
        </relatedPersonInfo>
        <relatedPersonInfo>
            <relatedPersonName>
                <firstName>Joseph</firstName>
                <middleName>D.</middleName>
                <lastName>Glatt</lastName>
            </relatedPersonName>
            <relatedPersonAddress>
                <street1>9 West 57th Street</street1>
                <city>New York</city>
                <stateOrCountry>NY</stateOrCountry>
                <stateOrCountryDescription>NEW YORK</stateOrCountryDescription>
                <zipCode>10019</zipCode>
            </relatedPersonAddress>
            <relatedPersonRelationshipList>
                <relationship>Executive Officer</relationship>
            </relatedPersonRelationshipList>
            <relationshipClarification>Executive Officer of the GP of the Issuer</relationshipClarification>
        </relatedPersonInfo>
        <relatedPersonInfo>
            <relatedPersonName>
                <firstName>Shari</firstName>
                <lastName>Verschell</lastName>
            </relatedPersonName>
            <relatedPersonAddress>
                <street1>9 West 57th Street</street1>
                <city>New York</city>
                <stateOrCountry>NY</stateOrCountry>
                <stateOrCountryDescription>NEW YORK</stateOrCountryDescription>
                <zipCode>10019</zipCode>
            </relatedPersonAddress>
            <relatedPersonRelationshipList>
                <relationship>Executive Officer</relationship>
            </relatedPersonRelationshipList>
            <relationshipClarification>Executive Officer of the GP of the Issuer</relationshipClarification>
        </relatedPersonInfo>
        <relatedPersonInfo>
            <relatedPersonName>
                <firstName>John</firstName>
                <middleName>J.</middleName>
                <lastName>Suydam</lastName>
            </relatedPersonName>
            <relatedPersonAddress>
                <street1>9 West 57th Street</street1>
                <city>New York</city>
                <stateOrCountry>NY</stateOrCountry>
                <stateOrCountryDescription>NEW YORK</stateOrCountryDescription>
                <zipCode>10019</zipCode>
            </relatedPersonAddress>
            <relatedPersonRelationshipList>
                <relationship>Executive Officer</relationship>
            </relatedPersonRelationshipList>
            <relationshipClarification>Executive Officer of the GP of the Issuer</relationshipClarification>
        </relatedPersonInfo>
        <relatedPersonInfo>
            <relatedPersonName>
                <firstName>Joshua</firstName>
                <middleName>J.</middleName>
                <lastName>Harris</lastName>
            </relatedPersonName>
            <relatedPersonAddress>
                <street1>9 West 57th Street</street1>
                <city>New York</city>
                <stateOrCountry>NY</stateOrCountry>
                <stateOrCountryDescription>NEW YORK</stateOrCountryDescription>
                <zipCode>10019</zipCode>
            </relatedPersonAddress>
            <relatedPersonRelationshipList>
                <relationship>Executive Officer</relationship>
            </relatedPersonRelationshipList>
            <relationshipClarification>Executive Officer of the GP of the Issuer</relationshipClarification>
        </relatedPersonInfo>
        <relatedPersonInfo>
            <relatedPersonName>
                <firstName>Anthony</firstName>
                <lastName>Civale</lastName>
            </relatedPersonName>
            <relatedPersonAddress>
                <street1>9 West 57th Street</street1>
                <city>New York</city>
                <stateOrCountry>NY</stateOrCountry>
                <stateOrCountryDescription>NEW YORK</stateOrCountryDescription>
                <zipCode>10019</zipCode>
            </relatedPersonAddress>
            <relatedPersonRelationshipList>
                <relationship>Executive Officer</relationship>
            </relatedPersonRelationshipList>
            <relationshipClarification>Executive Officer of the GP of the Issuer</relationshipClarification>
        </relatedPersonInfo>
        <relatedPersonInfo>
            <relatedPersonName>
                <firstName>William</firstName>
                <middleName>B.</middleName>
                <lastName>Kuesel</lastName>
            </relatedPersonName>
            <relatedPersonAddress>
                <street1>9 West 57th Street</street1>
                <city>New York</city>
                <stateOrCountry>NY</stateOrCountry>
                <stateOrCountryDescription>NEW YORK</stateOrCountryDescription>
                <zipCode>10019</zipCode>
            </relatedPersonAddress>
            <relatedPersonRelationshipList>
                <relationship>Executive Officer</relationship>
            </relatedPersonRelationshipList>
            <relationshipClarification>Executive Officer of the GP of the Issuer</relationshipClarification>
        </relatedPersonInfo>
        <relatedPersonInfo>
            <relatedPersonName>
                <firstName>Yael</firstName>
                <lastName>Levy</lastName>
            </relatedPersonName>
            <relatedPersonAddress>
                <street1>9 West 57th Street</street1>
                <city>New York</city>
                <stateOrCountry>NY</stateOrCountry>
                <stateOrCountryDescription>NEW YORK</stateOrCountryDescription>
                <zipCode>10019</zipCode>
            </relatedPersonAddress>
            <relatedPersonRelationshipList>
                <relationship>Executive Officer</relationship>
            </relatedPersonRelationshipList>
            <relationshipClarification>Executive Officer of the GP of the Issuer</relationshipClarification>
        </relatedPersonInfo>
        <relatedPersonInfo>
            <relatedPersonName>
                <firstName>Jessica</firstName>
                <middleName>L.</middleName>
                <lastName>Lomm</lastName>
            </relatedPersonName>
            <relatedPersonAddress>
                <street1>9 West 57th Street</street1>
                <city>New York</city>
                <stateOrCountry>NY</stateOrCountry>
                <stateOrCountryDescription>NEW YORK</stateOrCountryDescription>
                <zipCode>10019</zipCode>
            </relatedPersonAddress>
            <relatedPersonRelationshipList>
                <relationship>Executive Officer</relationship>
            </relatedPersonRelationshipList>
            <relationshipClarification>Executive Officer of the GP of the Issuer</relationshipClarification>
        </relatedPersonInfo>
        <relatedPersonInfo>
            <relatedPersonName>
                <firstName>Christian</firstName>
                <lastName>Weideman</lastName>
            </relatedPersonName>
            <relatedPersonAddress>
                <street1>9 West 57th Street</street1>
                <city>New York</city>
                <stateOrCountry>NY</stateOrCountry>
                <stateOrCountryDescription>NEW YORK</stateOrCountryDescription>
                <zipCode>10019</zipCode>
            </relatedPersonAddress>
            <relatedPersonRelationshipList>
                <relationship>Executive Officer</relationship>
            </relatedPersonRelationshipList>
            <relationshipClarification>Executive Officer of the GP of the Issuer</relationshipClarification>
        </relatedPersonInfo>
        <relatedPersonInfo>
            <relatedPersonName>
                <firstName>Laurie</firstName>
                <middleName>D.</middleName>
                <lastName>Medley</lastName>
            </relatedPersonName>
            <relatedPersonAddress>
                <street1>9 West 57th Street</street1>
                <city>New York</city>
                <stateOrCountry>NY</stateOrCountry>
                <stateOrCountryDescription>NEW YORK</stateOrCountryDescription>
                <zipCode>10019</zipCode>
            </relatedPersonAddress>
            <relatedPersonRelationshipList>
                <relationship>Executive Officer</relationship>
            </relatedPersonRelationshipList>
            <relationshipClarification>Executive Officer of the GP of the Issuer</relationshipClarification>
        </relatedPersonInfo>
        <relatedPersonInfo>
            <relatedPersonName>
                <firstName>Isabelle</firstName>
                <lastName>Gold</lastName>
            </relatedPersonName>
            <relatedPersonAddress>
                <street1>9 West 57th Street</street1>
                <city>New York</city>
                <stateOrCountry>NY</stateOrCountry>
                <stateOrCountryDescription>NEW YORK</stateOrCountryDescription>
                <zipCode>10019</zipCode>
            </relatedPersonAddress>
            <relatedPersonRelationshipList>
                <relationship>Executive Officer</relationship>
            </relatedPersonRelationshipList>
            <relationshipClarification>Executive Officer of the GP of the Issuer</relationshipClarification>
        </relatedPersonInfo>
        <relatedPersonInfo>
            <relatedPersonName>
                <firstName>John</firstName>
                <lastName>DeRosa</lastName>
            </relatedPersonName>
            <relatedPersonAddress>
                <street1>9 West 57th Street</street1>
                <city>New York</city>
                <stateOrCountry>NY</stateOrCountry>
                <stateOrCountryDescription>NEW YORK</stateOrCountryDescription>
                <zipCode>10019</zipCode>
            </relatedPersonAddress>
            <relatedPersonRelationshipList>
                <relationship>Executive Officer</relationship>
            </relatedPersonRelationshipList>
            <relationshipClarification>Executive Officer of the GP of the Issuer</relationshipClarification>
        </relatedPersonInfo>
        <relatedPersonInfo>
            <relatedPersonName>
                <firstName>Katherine</firstName>
                <middleName>G.</middleName>
                <lastName>Newman</lastName>
            </relatedPersonName>
            <relatedPersonAddress>
                <street1>9 West 57th Street</street1>
                <city>New York</city>
                <stateOrCountry>NY</stateOrCountry>
                <stateOrCountryDescription>NEW YORK</stateOrCountryDescription>
                <zipCode>10019</zipCode>
            </relatedPersonAddress>
            <relatedPersonRelationshipList>
                <relationship>Executive Officer</relationship>
            </relatedPersonRelationshipList>
            <relationshipClarification>Executive Officer of the GP of the Issuer</relationshipClarification>
        </relatedPersonInfo>
        <relatedPersonInfo>
            <relatedPersonName>
                <firstName>Martin</firstName>
                <middleName>B.</middleName>
                <lastName>Kelly</lastName>
            </relatedPersonName>
            <relatedPersonAddress>
                <street1>9 West 57th Street</street1>
                <city>New York</city>
                <stateOrCountry>NY</stateOrCountry>
                <stateOrCountryDescription>NEW YORK</stateOrCountryDescription>
                <zipCode>10019</zipCode>
            </relatedPersonAddress>
            <relatedPersonRelationshipList>
                <relationship>Executive Officer</relationship>
            </relatedPersonRelationshipList>
            <relationshipClarification>Executive Officer of the GP of the Issuer</relationshipClarification>
        </relatedPersonInfo>
        <relatedPersonInfo>
            <relatedPersonName>
                <firstName>Stephanie</firstName>
                <lastName>Drescher</lastName>
            </relatedPersonName>
            <relatedPersonAddress>
                <street1>9 West 57th Street</street1>
                <city>New York</city>
                <stateOrCountry>NY</stateOrCountry>
                <stateOrCountryDescription>NEW YORK</stateOrCountryDescription>
                <zipCode>10019</zipCode>
            </relatedPersonAddress>
            <relatedPersonRelationshipList>
                <relationship>Executive Officer</relationship>
            </relatedPersonRelationshipList>
            <relationshipClarification>Executive Officer of the GP of the Issuer</relationshipClarification>
        </relatedPersonInfo>
        <relatedPersonInfo>
            <relatedPersonName>
                <firstName>Matthew</firstName>
                <lastName>Breitfelder</lastName>
            </relatedPersonName>
            <relatedPersonAddress>
                <street1>9 West 57th Street</street1>
                <city>New York</city>
                <stateOrCountry>NY</stateOrCountry>
                <stateOrCountryDescription>NEW YORK</stateOrCountryDescription>
                <zipCode>10019</zipCode>
            </relatedPersonAddress>
            <relatedPersonRelationshipList>
                <relationship>Executive Officer</relationship>
            </relatedPersonRelationshipList>
            <relationshipClarification>Executive Officer of the GP of the Issuer</relationshipClarification>
        </relatedPersonInfo>
        <relatedPersonInfo>
            <relatedPersonName>
                <firstName>Agnieszka</firstName>
                <lastName>Rafalska</lastName>
            </relatedPersonName>
            <relatedPersonAddress>
                <street1>9 West 57th Street</street1>
                <city>New York</city>
                <stateOrCountry>NY</stateOrCountry>
                <stateOrCountryDescription>NEW YORK</stateOrCountryDescription>
                <zipCode>10019</zipCode>
            </relatedPersonAddress>
            <relatedPersonRelationshipList>
                <relationship>Executive Officer</relationship>
            </relatedPersonRelationshipList>
            <relationshipClarification>Executive Officer of the GP of the Issuer</relationshipClarification>
        </relatedPersonInfo>
        <relatedPersonInfo>
            <relatedPersonName>
                <firstName>Joshua</firstName>
                <lastName>Simpson</lastName>
            </relatedPersonName>
            <relatedPersonAddress>
                <street1>9 West 57th Street</street1>
                <city>New York</city>
                <stateOrCountry>NY</stateOrCountry>
                <stateOrCountryDescription>NEW YORK</stateOrCountryDescription>
                <zipCode>10019</zipCode>
            </relatedPersonAddress>
            <relatedPersonRelationshipList>
                <relationship>Executive Officer</relationship>
            </relatedPersonRelationshipList>
            <relationshipClarification>Executive Officer of the GP of the Issuer</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>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>
        </businessCombinationTransaction>
        <minimumInvestmentAccepted>1</minimumInvestmentAccepted>
        <salesCompensationList></salesCompensationList>
        <offeringSalesAmounts>
            <totalOfferingAmount>Indefinite</totalOfferingAmount>
            <totalAmountSold>0</totalAmountSold>
            <totalRemaining>Indefinite</totalRemaining>
        </offeringSalesAmounts>
        <investors>
            <hasNonAccreditedInvestors>false</hasNonAccreditedInvestors>
            <totalNumberAlreadyInvested>0</totalNumberAlreadyInvested>
        </investors>
        <salesCommissionsFindersFees>
            <salesCommissions>
                <dollarAmount>0</dollarAmount>
            </salesCommissions>
            <findersFees>
                <dollarAmount>0</dollarAmount>
            </findersFees>
            <clarificationOfResponse></clarificationOfResponse>
        </salesCommissionsFindersFees>
        <useOfProceeds>
            <grossProceedsUsed>
                <dollarAmount>0</dollarAmount>
            </grossProceedsUsed>
            <clarificationOfResponse></clarificationOfResponse>
        </useOfProceeds>
        <signatureBlock>
            <authorizedRepresentative>false</authorizedRepresentative>
            <signature>
                <issuerName>AIOF II Vanir Co-Invest B, L.P.</issuerName>
                <signatureName>/s/ James Elworth</signatureName>
                <nameOfSigner>James Elworth</nameOfSigner>
                <signatureTitle>Vice President of the General Partner of the Issuer</signatureTitle>
                <signatureDate>2021-10-26</signatureDate>
            </signature>
        </signatureBlock>
    </offeringData>
</edgarSubmission>
