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

    <schemaVersion>X0306</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2016-06-23</periodOfReport>

    <issuer>
        <issuerCik>0000827871</issuerCik>
        <issuerName>EAGLE PHARMACEUTICALS, INC.</issuerName>
        <issuerTradingSymbol>EGRX</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001674772</rptOwnerCik>
            <rptOwnerName>ProQuest Financial LLC</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>2430 VANDERBILT BEACH ROAD, #108-190</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>NAPLES</rptOwnerCity>
            <rptOwnerState>FL</rptOwnerState>
            <rptOwnerZipCode>34109</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001431818</rptOwnerCik>
            <rptOwnerName>ProQuest Investments IV, L.P.</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1></rptOwnerStreet1>
            <rptOwnerStreet2>2430 VANDERBILT BEACH ROAD, #108 - 190</rptOwnerStreet2>
            <rptOwnerCity>NAPLES</rptOwnerCity>
            <rptOwnerState>FL</rptOwnerState>
            <rptOwnerZipCode>34109</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001431819</rptOwnerCik>
            <rptOwnerName>ProQuest Associates IV LLC</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1></rptOwnerStreet1>
            <rptOwnerStreet2>2430 VANDERBILT BEACH ROAD, #108 - 190</rptOwnerStreet2>
            <rptOwnerCity>NAPLES</rptOwnerCity>
            <rptOwnerState>FL</rptOwnerState>
            <rptOwnerZipCode>34109</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001033508</rptOwnerCik>
            <rptOwnerName>Moorin Jay</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O PROQUEST INVESTMENTS</rptOwnerStreet1>
            <rptOwnerStreet2>2430 VANDERBILT BEACH ROAD, #108 - 190</rptOwnerStreet2>
            <rptOwnerCity>NAPLES</rptOwnerCity>
            <rptOwnerState>FL</rptOwnerState>
            <rptOwnerZipCode>34109</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001225149</rptOwnerCik>
            <rptOwnerName>SCHREIBER ALAIN</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O PROQUEST INVESTMENTS</rptOwnerStreet1>
            <rptOwnerStreet2>2430 VANDERBILT BEACH ROAD, #108 - 190</rptOwnerStreet2>
            <rptOwnerCity>NAPLES</rptOwnerCity>
            <rptOwnerState>FL</rptOwnerState>
            <rptOwnerZipCode>34109</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, $0.001 par value</value>
            </securityTitle>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>4770828</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>By ProQuest Investments IV, L.P.</value>
                    <footnoteId id="F1"/>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock $0,001 par value</value>
            </securityTitle>
            <transactionDate>
                <value>2016-06-23</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>J</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
                <footnoteId id="F3"/>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>9903</value>
                </transactionShares>
                <transactionPricePerShare>
                    <footnoteId id="F3"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>5582</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>By ProQuest Financial LLC</value>
                    <footnoteId id="F2"/>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <footnotes>
        <footnote id="F1">The shares are held by ProQuest Investments IV, L.P. (&quot;Investments IV&quot;), which ProQuest Financial LLC manages pursuant to a management agreement that was assigned from ProQuest Management LLC (&quot;ProQuest Management&quot;) to ProQuest Financial LLC (&quot;ProQuest Financial&quot;) in connection with an internal reorganization. Jay Moorin and Alain Schreiber are managing members of ProQuest Financial and each of them disclaims beneficial ownership of such securities except to the extent of his pecuniary interest in such securities.</footnote>
        <footnote id="F2">The shares are held in the ProQuest Management LLC Salary Savings Plan FBO Jay Moorin and for the benefit of certain other individuals. Jay Moorin and Alain Schreiber are trustees of the ProQuest Management LLC Salary Savings Plan FBO Jay Moorin and for the benefit of certain other individuals. Each of the Reporting Persons disclaims beneficial ownership of such securities except to the extent of each Reporting Person's pecuniary interest in such securities.</footnote>
        <footnote id="F3">The Reporting Persons transferred the shares from ProQuest Management LLC Salary Savings Plan FBO Jay Moorin and for the benefit of certain other individuals to an employee's separate IRA, with no additional consideration paid by the employee.</footnote>
    </footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>/s/ Pasquale DeAngelis</signatureName>
        <signatureDate>2016-06-30</signatureDate>
    </ownerSignature>
</ownershipDocument>
