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

    <schemaVersion>X0202</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2008-03-03</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0001201792</issuerCik>
        <issuerName>AMERICAN PUBLIC EDUCATION INC</issuerName>
        <issuerTradingSymbol>APEI</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001365552</rptOwnerCik>
            <rptOwnerName>Camden Partners Strategic Manager, LLC</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>500 EAST PRATT STREET</rptOwnerStreet1>
            <rptOwnerStreet2>SUITE 1200</rptOwnerStreet2>
            <rptOwnerCity>BALTIMORE</rptOwnerCity>
            <rptOwnerState>MD</rptOwnerState>
            <rptOwnerZipCode>21202</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001211905</rptOwnerCik>
            <rptOwnerName>BERKELEY RICHARD M</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O CAMDEN PARTNERS</rptOwnerStreet1>
            <rptOwnerStreet2>500 EAST PRATT STREET, SUITE 1200</rptOwnerStreet2>
            <rptOwnerCity>BALTIMORE</rptOwnerCity>
            <rptOwnerState>MD</rptOwnerState>
            <rptOwnerZipCode>21202</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001211899</rptOwnerCik>
            <rptOwnerName>HUGHES DONALD W</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O CAMDEN PARTNERS</rptOwnerStreet1>
            <rptOwnerStreet2>500 EAST PRATT STREET, SUITE 1200</rptOwnerStreet2>
            <rptOwnerCity>BALTIMORE</rptOwnerCity>
            <rptOwnerState>MD</rptOwnerState>
            <rptOwnerZipCode>21202</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001211913</rptOwnerCik>
            <rptOwnerName>JOHNSTON RICHARD M</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O CAMDEN PARTNERS</rptOwnerStreet1>
            <rptOwnerStreet2>500 EAST PRATT STREET, SUITE 1200</rptOwnerStreet2>
            <rptOwnerCity>BALTIMORE</rptOwnerCity>
            <rptOwnerState>MD</rptOwnerState>
            <rptOwnerZipCode>21202</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001025664</rptOwnerCik>
            <rptOwnerName>WARNOCK DAVID L</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O CAMDEN PARTNERS</rptOwnerStreet1>
            <rptOwnerStreet2>500 EAST PRATT STREET, SUITE 1200</rptOwnerStreet2>
            <rptOwnerCity>BALTIMORE</rptOwnerCity>
            <rptOwnerState>MD</rptOwnerState>
            <rptOwnerZipCode>21202</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001317017</rptOwnerCik>
            <rptOwnerName>Camden Partners Strategic III, LLC</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>500 EAST PRATT STREET, SUITE 1200</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>BALTIMORE</rptOwnerCity>
            <rptOwnerState>MD</rptOwnerState>
            <rptOwnerZipCode>21202</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001283497</rptOwnerCik>
            <rptOwnerName>CAMDEN PARTNERS STRATEGIC FUND III LP</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>500 EAST PRATT STREET, SUITE 1200</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>BALTIMORE</rptOwnerCity>
            <rptOwnerState>MD</rptOwnerState>
            <rptOwnerZipCode>21202</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001283498</rptOwnerCik>
            <rptOwnerName>CAMDEN PARTNERS STRATEGIC FUND III-A LP</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>500 EAST PRATT STREET, SUITE 1200</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>BALTIMORE</rptOwnerCity>
            <rptOwnerState>MD</rptOwnerState>
            <rptOwnerZipCode>21202</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock, par value $.01</value>
            </securityTitle>
            <transactionDate>
                <value>2008-03-03</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>S</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>176460</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>33.5475</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>834888</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>See Footnote</value>
                    <footnoteId id="F1"/>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <footnotes>
        <footnote id="F1">Consists of 800,282, 33,258, and 1,348 shares of Common stock directly owned by Fund III, Fund III-A and David L. Warnock, respectively. CPSM, CPS III and the Managing Members may be deemed indirect beneficial owners of the Common Stock owned by the Funds as a result of the relationships described in the Remarks section. CPSM, CPS III and each of the Managing Members disclaims beneficial ownership of the Common Stock held directly by the Funds and David L. Warnock, except to the extent of its or his pecuniary interest therein. Each of the Funds and David L. Warnock disclaims beneficial ownership of the Common Stock held by the other, except to the extent of its or his pecuniary interest therein.</footnote>
    </footnotes>

    <remarks>This report is being filed by Camden Partners Strategic Manager, LLC, as the managing member of Camden Partners Strategic III, LLC. This report includes reports by members of Camden Partners Strategic Fund III, L.P. and Camden Partners Strategic Fund III-A, L.P. This report is being filed jointly by Camden Partners Strategic Manager, LLC (&quot;CPSM&quot;), Camden Partners Strategic III, LLC (&quot;CPS III&quot;), Camden Partners Strategic Fund III, L.P. (&quot;Fund III), Camden Partners Strategic Fund III-A, L.P. (&quot;Fund III-A&quot;), Donald W. Hughes, David L. Warnock, Richard M. Johnston and Richard M. Berkeley (the &quot;Managing Members&quot;) (collectively, the &quot;Reporting Persons&quot;). The Managing Members are the managing members of CPSM, which is the managing member of CPS III. CPS III is the General Partner of Fund III and Fund III-A (such funds together, the &quot;Funds&quot;). The Funds may each be deemed a director by deputization as a result of David L. Warnock, a managing member of CPSM, serving on the board of directors of American Public Education, Inc.</remarks>

    <ownerSignature>
        <signatureName>By: /s/ Donald W. Hughes, Managing Member</signatureName>
        <signatureDate>2008-03-05</signatureDate>
    </ownerSignature>

    <ownerSignature>
        <signatureName>/s/ Donald W. Hughes, Attorney-in-Fact</signatureName>
        <signatureDate>2008-03-05</signatureDate>
    </ownerSignature>

    <ownerSignature>
        <signatureName>/s/ Donald W. Hughes</signatureName>
        <signatureDate>2008-03-05</signatureDate>
    </ownerSignature>

    <ownerSignature>
        <signatureName>/s/ Donald W. Hughes, Attorney-in-Fact</signatureName>
        <signatureDate>2008-03-05</signatureDate>
    </ownerSignature>

    <ownerSignature>
        <signatureName>/s/ Donald W. Hughes, Attorney-in-Fact</signatureName>
        <signatureDate>2008-03-05</signatureDate>
    </ownerSignature>

    <ownerSignature>
        <signatureName>By Donald W. Hughes, Managing Member</signatureName>
        <signatureDate>2008-03-05</signatureDate>
    </ownerSignature>

    <ownerSignature>
        <signatureName>By Camden Partners Strategic III, LLC, its General Partner, By  Camden Partners Strategic Manager, LLC, its Managing Member, By Donald W. Hughes, Managing Member</signatureName>
        <signatureDate>2008-03-05</signatureDate>
    </ownerSignature>

    <ownerSignature>
        <signatureName>By Camden Partners Strategic III, LLC, its General Partner, By  Camden Partners Strategic Manager, LLC, its Managing Member, By Donald W. Hughes, Managing Member</signatureName>
        <signatureDate>2008-03-05</signatureDate>
    </ownerSignature>
</ownershipDocument>
