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

    <schemaVersion>X0609</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2026-08-12</periodOfReport>

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

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001717441</rptOwnerCik>
            <rptOwnerName>Sukhtian Ghiath M.</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerNonUSAddressFlag>true</rptOwnerNonUSAddressFlag>
            <rptOwnerStreet1>7TH CIRCLE, ZAHRAN ST.</rptOwnerStreet1>
            <rptOwnerStreet2>ZAHRAN PLAZA BUILDING, 4TH FLOOR</rptOwnerStreet2>
            <rptOwnerCity>AMMAN</rptOwnerCity>
            <rptOwnerNonUSStateTerritory></rptOwnerNonUSStateTerritory>
            <rptOwnerCountry>M2</rptOwnerCountry>
            <rptOwnerZipCode>11844</rptOwnerZipCode>
            <rptOwnerStateDescription>JORDAN</rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>true</isDirector>
            <isOfficer>false</isOfficer>
            <isTenPercentOwner>true</isTenPercentOwner>
            <isOther>false</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001804598</rptOwnerCik>
            <rptOwnerName>GMS Ventures &amp; Investments</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerNonUSAddressFlag>true</rptOwnerNonUSAddressFlag>
            <rptOwnerStreet1>C/O INTERTRUST CORP. SVCS. (CAYMAN) LTD.</rptOwnerStreet1>
            <rptOwnerStreet2>190 ELGIN AVENUE</rptOwnerStreet2>
            <rptOwnerCity>GEORGE TOWN</rptOwnerCity>
            <rptOwnerNonUSStateTerritory></rptOwnerNonUSStateTerritory>
            <rptOwnerCountry>E9</rptOwnerCountry>
            <rptOwnerZipCode>KY1-9007</rptOwnerZipCode>
            <rptOwnerStateDescription>CAYMAN ISLANDS</rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>true</isDirector>
            <isOfficer>false</isOfficer>
            <isTenPercentOwner>true</isTenPercentOwner>
            <isOther>false</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <aff10b5One>false</aff10b5One>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2026-08-12</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>P</transactionCode>
                <equitySwapInvolved>false</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>2525252</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0.99</value>
                    <footnoteId id="F1"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>24617320</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>See footnote</value>
                    <footnoteId id="F3"/>
                    <footnoteId id="F4"/>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <derivativeTable>
        <derivativeTransaction>
            <securityTitle>
                <value>Warrants (right to buy)</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>1.10</value>
            </conversionOrExercisePrice>
            <transactionDate>
                <value>2026-08-12</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>P</transactionCode>
                <equitySwapInvolved>false</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>2525252</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0</value>
                    <footnoteId id="F1"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <exerciseDate>
                <value>2026-08-14</value>
                <footnoteId id="F2"/>
            </exerciseDate>
            <expirationDate>
                <value>2031-08-14</value>
                <footnoteId id="F2"/>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>2525252</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>2525252</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>See footnote</value>
                    <footnoteId id="F3"/>
                    <footnoteId id="F4"/>
                </natureOfOwnership>
            </ownershipNature>
        </derivativeTransaction>
    </derivativeTable>

    <footnotes>
        <footnote id="F1">On August 12, 2026, the Issuer entered into an underwriting agreement with Piper Sandler &amp; Co. and BTIG, LLC, as representatives of the several underwriters named therein, relating to an underwritten public offering by the Issuer of shares of its common stock and accompanying warrants to purchase shares of common stock at a combined public offering price of $0.99 per share of common stock and accompanying warrant. The offering closed on August 14, 2026. The price reported in Table I above represents the combined public offering price for one share of common stock and one accompanying warrant to purchase one share of common
stock; no separate consideration was paid for the accompanying warrants, and accordingly the price of the derivative security reported in Table II above is $0.00.</footnote>
        <footnote id="F2">The warrants were exercisable immediately upon issuance and expire five years from the date of issuance, on August 14, 2031. The warrants are subject to a beneficial ownership limitation that prohibits exercise to the extent the holder, together with its affiliates and other attribution parties, would beneficially own more than the applicable percentage of the Issuer's outstanding common stock immediately after giving effect to such exercise.</footnote>
        <footnote id="F3">These securities are held of record by GMS Ventures. Ghiath M. Sukhtian (&quot;Ghiath Sukhtian&quot;), a natural person, is the holder of a controlling interest in GMS Ventures. GMS Ventures has designated two representatives to serve on the Issuer's board of directors. Therefore, each of GMS Ventures and Ghiath Sukhtian may be deemed a director by deputization.</footnote>
        <footnote id="F4">By virtue of the relationships described above in Footnote 3, Ghiath Sukhtian may be deemed to have voting and investment power with respect to the securities held by GMS Ventures 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. This report shall not be deemed an admission that any of the Reporting
Persons are the beneficial owners of such securities for the purpose of Section 16 of the Exchange Act, or for any other purpose.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>/s/ Ghiath M. Sukhtian, By: Lawrence Kenyon, Attorney-in-Fact</signatureName>
        <signatureDate>2026-08-14</signatureDate>
    </ownerSignature>

    <ownerSignature>
        <signatureName>/s/ GMS Ventures and Investments, By: Lawrence Kenyon, Attorney-in-Fact</signatureName>
        <signatureDate>2026-08-14</signatureDate>
    </ownerSignature>
</ownershipDocument>
