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

    <schemaVersion>X0303</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2008-10-22</periodOfReport>

    <notSubjectToSection16>1</notSubjectToSection16>

    <issuer>
        <issuerCik>0001165460</issuerCik>
        <issuerName>Lexington Master Limited Partnership</issuerName>
        <issuerTradingSymbol>N/A</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001448690</rptOwnerCik>
            <rptOwnerName>AP LXP Holdings, LLC</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>TWO MANHATTANVILLE ROAD SUITE 204</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>PURCHASE</rptOwnerCity>
            <rptOwnerState>NY</rptOwnerState>
            <rptOwnerZipCode>10577</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001210237</rptOwnerCik>
            <rptOwnerName>APOLLO REAL ESTATE INVESTMENT FUND III LP</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1></rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity></rptOwnerCity>
            <rptOwnerState></rptOwnerState>
            <rptOwnerZipCode></rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001247182</rptOwnerCik>
            <rptOwnerName>APOLLO REAL ESTATE ADVISORS III L P</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>TWO MANHATTANVILLE ROAD</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>PURCHASE</rptOwnerCity>
            <rptOwnerState>NY</rptOwnerState>
            <rptOwnerZipCode>10577</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001247180</rptOwnerCik>
            <rptOwnerName>APOLLO REAL ESTATE CAPITAL ADVISORS III INC</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>TWO MANHATTANVILLE ROAD</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>PURCHASE</rptOwnerCity>
            <rptOwnerState>NY</rptOwnerState>
            <rptOwnerZipCode>10577</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Units of Limited Partnership Interest</value>
            </securityTitle>
            <transactionDate>
                <value>2008-10-22</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>C</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
                <footnoteId id="F1"/>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>18687236</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0</value>
                    <footnoteId id="F2"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>0</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                    <footnoteId id="F3"/>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <footnotes>
        <footnote id="F1">Units were redeemed for shares of common stock in Lexington Realty Trust in accordance with the terms of The Lexington Master Limited Partnership's partnership agreement.</footnote>
        <footnote id="F2">Each unit was converted for one share of Lexington Realty Trust common stock.</footnote>
        <footnote id="F3">AP LXP Holdings, LLC, a Delaware limited liability company (&quot;AP LXP&quot;), holds the shares directly.  Apollo Real Estate Investment Fund III, L.P., a Delaware limited partnership (&quot;AREIF III&quot;), is the sole member of AP LXP.  Apollo Real Estate Advisors III, L.P., a Delaware limited partnership (&quot;AREA III&quot;), is the general partner of AREIF III, and Apollo Capital Advisors III, Inc., a Delaware corporation, is the general partner of AREA III.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>AP LXP Holdings, LLC, by Stuart Koenig, Vice President</signatureName>
        <signatureDate>2008-10-22</signatureDate>
    </ownerSignature>

    <ownerSignature>
        <signatureName>Apollo Real Estate Investment Fund III, L.P., by Apollo Real Estate Advisors III, L.P., its general partner, by Apollo Capital Advisors III, Inc., its general partner, by Stuart Koenig, Vice President</signatureName>
        <signatureDate>2008-10-22</signatureDate>
    </ownerSignature>

    <ownerSignature>
        <signatureName>Apollo Real Estate Advisors III, L.P., its general partner, by Apollo Capital Advisors III, Inc., its general partner, by Stuart Koenig, Vice President</signatureName>
        <signatureDate>2008-10-22</signatureDate>
    </ownerSignature>

    <ownerSignature>
        <signatureName>Apollo Capital Advisors III, Inc., by Stuart Koenig, Vice President</signatureName>
        <signatureDate>2008-10-22</signatureDate>
    </ownerSignature>
</ownershipDocument>
