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

    <schemaVersion>X0306</schemaVersion>

    <documentType>4/A</documentType>

    <periodOfReport>2018-09-30</periodOfReport>

    <dateOfOriginalSubmission>2018-10-02</dateOfOriginalSubmission>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0001649989</issuerCik>
        <issuerName>Outlook Therapeutics, Inc.</issuerName>
        <issuerTradingSymbol>OTLK</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001716335</rptOwnerCik>
            <rptOwnerName>BioLexis Pte Ltd.</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>36 ROBINSON ROAD</rptOwnerStreet1>
            <rptOwnerStreet2>#13-01 CITY HOUSE</rptOwnerStreet2>
            <rptOwnerCity>SINGAPORE</rptOwnerCity>
            <rptOwnerState>U0</rptOwnerState>
            <rptOwnerZipCode>068877</rptOwnerZipCode>
            <rptOwnerStateDescription>SINGAPORE</rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001717437</rptOwnerCik>
            <rptOwnerName>Pillai Arun Kumar</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>#30, 1ST MAIN</rptOwnerStreet1>
            <rptOwnerStreet2>J.P. NAGAR 3RD PHASE</rptOwnerStreet2>
            <rptOwnerCity>BANGALORE</rptOwnerCity>
            <rptOwnerState>K7</rptOwnerState>
            <rptOwnerZipCode>560078</rptOwnerZipCode>
            <rptOwnerStateDescription>INDIA</rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001716033</rptOwnerCik>
            <rptOwnerName>Sukhtian Faisal Ghiath</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>7TH CIRCLE, ZAHRAN STREET</rptOwnerStreet1>
            <rptOwnerStreet2>ZAHRAN PLAZA BLDG, 4TH FLOOR</rptOwnerStreet2>
            <rptOwnerCity>AMMAN</rptOwnerCity>
            <rptOwnerState>M2</rptOwnerState>
            <rptOwnerZipCode>11844</rptOwnerZipCode>
            <rptOwnerStateDescription>JORDAN</rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <derivativeTable>
        <derivativeTransaction>
            <securityTitle>
                <value>Series A-1 Convertible Preferred Stock</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <footnoteId id="F1"/>
            </conversionOrExercisePrice>
            <transactionDate>
                <value>2018-09-30</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>J</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
                <footnoteId id="F2"/>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>1468</value>
                    <footnoteId id="F2"/>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0.00</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <exerciseDate>
                <footnoteId id="F1"/>
            </exerciseDate>
            <expirationDate>
                <footnoteId id="F1"/>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>221937</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>60203</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                    <footnoteId id="F3"/>
                    <footnoteId id="F4"/>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeTransaction>
    </derivativeTable>

    <footnotes>
        <footnote id="F1">Each share of the Series A-1 Convertible Preferred Stock (the &quot;Series A-1&quot;) is convertible into shares of the Issuer's common stock, par value $0.01 per share (&quot;Shares&quot;) at any time at the election of the holder. The Series A-1 has no expiration date.</footnote>
        <footnote id="F2">Represents shares of Series A-1 received by BioLexis Pte Ltd. (&quot;BioLexis&quot;) as a payment-in-kind dividend on previously acquired Series A-1.</footnote>
        <footnote id="F3">These securities are held of record by BioLexis. Tenshi Life Sciences Private Limited (&quot;Tenshi&quot;), a private investment vehicle controlled by Arun Kumar Pillai (&quot;Kumar&quot;), and GMS Pharma (Singapore) Pte. Limited (&quot;GMS Pharma&quot;), a private investment company and wholly-owned subsidiary of GMS Holdings, are the 50:50 beneficial owners of BioLexis, in which each of Tenshi and GMS Pharma owns 50% of the outstanding voting shares. Kumar, a natural person, is the holder of a controlling interest in Tenshi. Ghiath M. Sukhtian (&quot;Ghiath Sukhtian&quot;), a natural person, is the holder of a controlling interest in GMS Holdings, which is the holder of a controlling interest in GMS Pharma.</footnote>
        <footnote id="F4">By virtue of the relationships described above in Footnote 3, Kumar and Ghiath Sukhtian may be deemed to have voting and investment power with respect to the securities held by BioLexis noted above and as a result may be deemed to beneficially own such securities for purposes of Rule 13d-3 under the Securities Exchange Act of 1934, as amended (the &quot;Exchange Act&quot;). The Reporting Persons disclaim beneficial ownership of the securities reported herein for purposes of Rule 16a-1(a) under the Exchange Act, except to the extent of its or his pecuniary interest therein, if any. BioLexis has designated four representatives to serve on the Issuer's board of directors. This report shall not be deemed an admission that any of the Reporting Persons are the beneficial owner of such securities for the purpose of Section 16 of the Exchange Act, or for any other purpose.</footnote>
    </footnotes>

    <remarks>This Form 4/A to Form 4 filed with the Securities and Exchange Commission on 10/2/2018 is being filed to report the correct number of shares acquired and their corresponding underlying securities in Columns 5 and 7, respectively. The Reporting Person received 1,468 shares of Series A-1 Convertible Preferred Securities convertible into 221,937 shares of Common Stock on September 30, 2018 instead of the amount previously reported.</remarks>

    <ownerSignature>
        <signatureName>/s/ Faisal G. Sukhtian</signatureName>
        <signatureDate>2018-12-31</signatureDate>
    </ownerSignature>

    <ownerSignature>
        <signatureName>/s/ Arun Kumar Pillai</signatureName>
        <signatureDate>2018-12-31</signatureDate>
    </ownerSignature>

    <ownerSignature>
        <signatureName>/s/ Ghiath M. Sukhtian</signatureName>
        <signatureDate>2018-12-31</signatureDate>
    </ownerSignature>
</ownershipDocument>
