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

    <schemaVersion>X0303</schemaVersion>

    <documentType>5</documentType>

    <periodOfReport>2009-12-31</periodOfReport>

    <notSubjectToSection16>1</notSubjectToSection16>

    <form3HoldingsReported>0</form3HoldingsReported>

    <form4TransactionsReported>0</form4TransactionsReported>

    <issuer>
        <issuerCik>0001328208</issuerCik>
        <issuerName>JK Acquisition Corp.</issuerName>
        <issuerTradingSymbol>JKAK</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001357643</rptOwnerCik>
            <rptOwnerName>WEISS ANDREW M</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>29 COMMONWEALTH AVE.</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>BOSTON</rptOwnerCity>
            <rptOwnerState>MA</rptOwnerState>
            <rptOwnerZipCode>02116</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeHolding>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionCoding>
                <transactionFormType></transactionFormType>
            </transactionCoding>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>1343303</value>
                    <footnoteId id="F1"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>See Footnote 1</value>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
    </nonDerivativeTable>

    <derivativeTable>
        <derivativeHolding>
            <securityTitle>
                <value>Warrants</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>15</value>
            </conversionOrExercisePrice>
            <transactionCoding>
                <transactionFormType></transactionFormType>
            </transactionCoding>
            <exerciseDate>
                <footnoteId id="F2"/>
            </exerciseDate>
            <expirationDate>
                <value>2010-04-10</value>
                <footnoteId id="F2"/>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>23700</value>
                    <footnoteId id="F1"/>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>23700</value>
                    <footnoteId id="F1"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>See Footnote 1</value>
                </natureOfOwnership>
            </ownershipNature>
        </derivativeHolding>
    </derivativeTable>

    <footnotes>
        <footnote id="F1">Shares reported herein represent shares beneficially owned by (i) a private investment partnership of which Mr. Weiss is the Managing Member of the General Partner and (ii) a private investment corporation of which Mr. Weiss is the Managing Member of the Investment Manager. Mr. Weiss disclaims beneficial ownership of the shares reported herein except to the extent of his pecuniary interest therein.</footnote>
        <footnote id="F2">There is currently no exercise date for the warrants, which only become exercisable after the acquisition is approved. Each warrant will become exercisable only on the completion of a business combination and will expire on April 10, 2010 or earlier upon redemption.</footnote>
    </footnotes>

    <remarks>On December 29, 2009 the issuer announced that it had issued 122,192,326 additional shares of common stock to third parties.  As a result, the reporting person is no longer a 10% owner with respect to the issuer.</remarks>

    <ownerSignature>
        <signatureName>Georgiy Nikitin, Attorney-In-Fact for Andrew Weiss</signatureName>
        <signatureDate>2010-02-12</signatureDate>
    </ownerSignature>
</ownershipDocument>
