UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM 8-K

CURRENT REPORT

PURSUANT TO SECTION 13 OR 15(d)

OF THE SECURITIES EXCHANGE ACT OF 1934

Date of Report (Date of earliest event reported) March 17, 2016

LEGG MASON, INC.

(Exact name of registrant as specified in its charter)

Registrant’s telephone number, including area code: 410 539-0000

Not Applicable

(Former name or former address if changed since last report)

Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions:

On March 22, 2016, Legg Mason, Inc. (the “Company”) completed the closing of the issuance and sale of $450,000,000 aggregate principal amount of the Company’s 4.750% Senior Notes due 2026 (the “Notes”).

The Notes were issued pursuant to an indenture, dated as of January 22, 2014 (the “Base Indenture”), as supplemented by the Fourth Supplemental Indenture, dated as of March 22, 2016 (the “Fourth Supplemental Indenture” and, together with the Base Indenture, the “Indenture”), in each case between the Company and The Bank of New York Mellon, as trustee. The Notes have been registered under the Securities Act of 1933, as amended, by a Registration Statement on Form S-3ASR (Registration No. 333-209616) which became effective February 19, 2016 (the “Registration Statement”). The terms of the Notes are described in the Company’s prospectus dated February 19, 2016, as supplemented by the final prospectus supplement dated March 17, 2016, as filed with the Securities Exchange Commission on March 18, 2016; the prospectus as so supplemented forms part of the Registration Statement. A copy of the Base Indenture was filed as Exhibit 4.1 to the Registration Statement and is incorporated herein by reference. A copy of the Fourth Supplemental Indenture and the form of the Note are attached hereto as Exhibits 4.2 and 4.3, respectively, and are incorporated herein by reference.

A copy of the opinions of Thomas C. Merchant, Executive Vice President and General Counsel of the Company, and Shearman & Sterling LLP, counsel to the Company, relating to the validity of the Notes are attached hereto as Exhibits 5.1 and 5.2, respectively.

Please see the discussion set forth under Item 1.01, “Entry into a Material Definitive Agreement,” of this Form 8-K, which discussion is incorporated herein by reference.

On March 17, 2016, the Company entered into an underwriting agreement (the “Underwriting Agreement”) with Citigroup Global Markets Inc. and J.P. Morgan Securities LLC, as representatives of the underwriters named therein. A copy of the Underwriting Agreement is attached hereto as Exhibit 1.1 and is incorporated herein by reference.

SIGNATURES

Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned hereunto duly authorized.

LEGG MASON, INC.

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