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

    <schemaVersion>X0306</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2018-02-22</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0001577791</issuerCik>
        <issuerName>Oaktree Strategic Income Corp</issuerName>
        <issuerTradingSymbol>OCSI</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0000949509</rptOwnerCik>
            <rptOwnerName>OAKTREE CAPITAL MANAGEMENT LP</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>333 SOUTH GRAND AVENUE, 28TH FLOOR</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>LOS ANGELES</rptOwnerCity>
            <rptOwnerState>CA</rptOwnerState>
            <rptOwnerZipCode>90071</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001403382</rptOwnerCik>
            <rptOwnerName>Oaktree Holdings, Inc.</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>333 SOUTH GRAND AVENUE</rptOwnerStreet1>
            <rptOwnerStreet2>28TH FLOOR</rptOwnerStreet2>
            <rptOwnerCity>LOS ANGELES</rptOwnerCity>
            <rptOwnerState>CA</rptOwnerState>
            <rptOwnerZipCode>90071</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001403528</rptOwnerCik>
            <rptOwnerName>Oaktree Capital Group, LLC</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>333 SOUTH GRAND AVENUE</rptOwnerStreet1>
            <rptOwnerStreet2>28TH FLOOR</rptOwnerStreet2>
            <rptOwnerCity>LOS ANGELES</rptOwnerCity>
            <rptOwnerState>CA</rptOwnerState>
            <rptOwnerZipCode>90071</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001403525</rptOwnerCik>
            <rptOwnerName>Oaktree Capital Group Holdings GP, LLC</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>333 SOUTH GRAND AVENUE</rptOwnerStreet1>
            <rptOwnerStreet2>28TH FLOOR</rptOwnerStreet2>
            <rptOwnerCity>LOS ANGELES</rptOwnerCity>
            <rptOwnerState>CA</rptOwnerState>
            <rptOwnerZipCode>90071</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2018-02-22</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>P</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>23700</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>7.718</value>
                    <footnoteId id="F1"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>128700</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>By Oaktree Capital I, L.P.</value>
                    <footnoteId id="F3"/>
                    <footnoteId id="F4"/>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2018-02-23</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>P</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>23700</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>7.7172</value>
                    <footnoteId id="F2"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>152400</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>By Oaktree Capital I, L.P.</value>
                    <footnoteId id="F3"/>
                    <footnoteId id="F4"/>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <footnotes>
        <footnote id="F1">The shares reported as purchased on February 22, 2018 were purchased in multiple transactions at actual purchase prices ranging from $7.67 to $7.73 per share. The price reported reflects the weighted average purchase price for the transactions. The Reporting Persons undertake to provide, upon request by the staff of the Securities and Exchange Commission, the Issuer or a security holder of the Issuer, full information regarding the number of shares purchased at each separate price.</footnote>
        <footnote id="F2">The shares reported as purchased on February 23, 2018 were purchased in multiple transactions at actual purchase prices ranging from $7.70 to $7.72 per share. The price reported reflects the weighted average purchase price for the transactions. The Reporting Persons undertake to provide, upon request by the staff of the Securities and Exchange Commission, the Issuer or a security holder of the Issuer, full information regarding the number of shares purchased at each separate price.</footnote>
        <footnote id="F3">Oaktree Capital I, L.P., a Delaware limited partnership (&quot;Capital I&quot;) purchased shares of the common stock (the &quot;Common Stock&quot;) of Oaktree Specialty Lending Corporation (&quot;Issuer&quot;) on the open market. OCM Holdings I, LLC, a Delaware limited liability company (&quot;Holdings I&quot;), serves as the general partner of Capital I. Oaktree Holdings, LLC, a Delaware limited liability company (&quot;Holdings&quot;), serves as the managing member of Holdings I. Oaktree Capital Group, LLC, a Delaware limited liability company (&quot;OCG&quot;) and a Reporting Person for the purposes of this Form 4, serves as the managing member of Holdings. Oaktree Capital Group Holdings GP, LLC, a Delaware limited liability company and a Reporting Person for the purposes of this Form 4, serves as the duly elected manager of OCG.</footnote>
        <footnote id="F4">On July 13, 2017, Oaktree Capital Management, L.P. (&quot;Oaktree&quot;) entered into a Voting Agreement, dated as of July 13, 2017 (the &quot;Voting Agreement&quot;), with Fifth Street Holdings, L.P., Leonard M. Tannenbaum, the Leonard M. Tannenbaum Foundation and the Tannenbaum Family 2012 Trust (collectively, the &quot;Stockholders&quot;) with respect to the shares of common stock, par value $0.01 per share, of the Issuer (the &quot;Common Stock&quot;) owned by the Stockholders. As a result, Oaktree and the other Reporting Persons may be deemed to beneficially own, pursuant to Rule 13d-3 under the Securities Exchange Act of 1934, as amended, in excess of 10% of the issued and outstanding Common Stock. See the Form 3 filed by the Reporting Persons with the Securities and Exchange Commission on July 21, 2017 with respect to the Issuer for additional information.</footnote>
    </footnotes>

    <remarks>Each Reporting Person disclaims beneficial ownership of all equity securities reported herein except to the extent of its respective pecuniary interest therein, and the filing of this Form 4 shall not be construed as an admission that any such Reporting Person is the beneficial owner of any equity securities covered by this Form 4.</remarks>

    <ownerSignature>
        <signatureName>See Signatures Included in Exhibit 99.1</signatureName>
        <signatureDate>2018-02-23</signatureDate>
    </ownerSignature>
</ownershipDocument>
