OCSL Oaktree Specialty Lending Corporation

Filed Pursuant to Rule 433

Issuer Free Writing Prospectus dated February 13, 2020

Relating to Preliminary Prospectus Supplement dated February 13, 2020 and

Prospectus dated January 13, 2020

Registration No. 333-234798

Oaktree Specialty Lending Corporation

$300,000,000

3.500% Notes due 2025

PRICING TERM SHEET

February 13, 2020

The following sets forth the final terms of the 3.500% Notes due 2025 and should only be read together with the preliminary prospectus supplement dated February 13, 2020, together with the accompanying prospectus dated January 13, 2020 relating to these securities (the “Preliminary Prospectus”), and supersedes the information in the Preliminary Prospectus to the extent inconsistent with the information in the Preliminary Prospectus. In all other respects, this pricing term sheet is qualified in its entirety by reference to the Preliminary Prospectus. Terms used herein but not defined herein shall have the respective meanings as set forth in the Preliminary Prospectus. All references to dollar amounts are references to U.S. dollars.

Notes:

purchasers who wish to trade the Notes prior to the date of delivery hereunder will be required, by virtue of the fact that the Notes initially will settle in T+7 business days, to specify an alternative settlement arrangement at the time of any such trade to prevent a failed settlement.

Investors are advised to carefully consider the investment objectives, risks, charges and expenses of Oaktree Specialty Lending Corporation before investing. The Preliminary Prospectus, which has been filed with the Securities and Exchange Commission (the “SEC”), contains this and other information about Oaktree Specialty Lending Corporation and should be read carefully before investing.

The Preliminary Prospectus and this pricing term sheet are not offers to sell any securities of Oaktree Specialty Lending Corporation and are not soliciting an offer to buy such securities in any state or jurisdiction where such offer and sale is not permitted.

Oaktree Specialty Lending Corporation has filed a shelf registration statement (including a prospectus) with the SEC for the offering to which this communication relates. Before you invest, you should read the prospectus in that registration statement, the Preliminary Prospectus and other documents Oaktree Specialty Lending Corporation has filed with the SEC for more complete information about Oaktree Specialty Lending Corporation and this offering. You may get these documents for free by visiting EDGAR on the SEC Web site at www.sec.gov. Alternatively, Oaktree Specialty Lending Corporation, any underwriter or any dealer participating in the offering will arrange to send you the prospectus supplement and accompanying prospectus if you request it from J.P. Morgan Securities LLC at 383 Madison Avenue, New York, NY 10179, Attn: Investment Grade Syndicate Desk, facsimile: 212-834-6081; BofA Securities, Inc. at 200 North College Street, NC1-004-03-43, Charlotte, NC 28255-0001, Attention: Prospectus Department, Ph.: 1-800-294-1322; RBC Capital Markets, LLC at 200 Vesey Street, 8th Floor, New York, NY 10281, Attention: Transaction Management, facsimile: 212-658-6137; or ING Financial Markets LLC at 1133 Avenue of the Americas, New York, NY 10036, Attention: Investment Grade Syndicate Desk, facsimile: 646-424-6718.