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): November 16, 2016

FRANKLIN FINANCIAL NETWORK, INC.

(Exact name of registrant as specified in charter)

722 Columbia Avenue, Franklin, Tennessee 37064

(Address of Principal Executive Offices)

615-236-2265

(Registrant’s Telephone Number, Including Area Code)

(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 November 16, 2016, Franklin Financial Network, Inc. (the “Company”) entered into an underwriting agreement (the “Underwriting Agreement”) with Raymond James & Associates, Inc., as representative of the several underwriters named therein (collectively, the “Underwriters”), to issue and sell 1,950,000 shares of the Company’s common stock, no par value per share (“Common Stock”), at a public offering price of $32.00 per share in an underwritten public offering (the “Offering”). As part of the Offering, the Company granted the Underwriters a 30-day option to purchase up to an additional 292,500 shares of Common Stock to cover over-allotments, if any (the “Over-Allotment Option”). The Underwriters elected to exercise the Over-Allotment Option in full on November 17, 2016. The Offering was completed on November 21, 2016 pursuant to the terms of the Underwriting Agreement. The underwriting discounts and commissions were $1.76 per share sold in the Offering. The net proceeds of the Offering, after underwriting discounts and estimated expenses, and with exercise of the Over-Allotment Option, were approximately $67.5 million.

The Underwriting Agreement contains customary representations, warranties and covenants among the parties as of the date of entering into such Underwriting Agreement. These representations, warranties and covenants are not factual information to investors about the Company. A copy of the Underwriting Agreement is filed as Exhibit 1.1 to this Current Report on Form 8-K and is incorporated herein by reference. The description of the material terms of the Underwriting Agreement is qualified in its entirety by reference to Exhibit 1.1 to this Current Report on Form 8-K.

Pursuant to the Underwriting Agreement, directors and certain executive officers of the Company entered into agreements in substantially the form included as an exhibit to the Underwriting Agreement providing for a 90-day “lock-up” period with respect to sales of specified securities, subject to certain exceptions.

The offer and sale of shares of Common Stock sold in the Offering were registered under the Securities Act of 1933, as amended, pursuant to a shelf registration statement on Form S-3 (Registration No. 333-208578) declared effective by the Securities and Exchange Commission on December 23, 2015 (the “Registration Statement”), and a registration statement on Form S-3 (Registration No. 333-214629) which became effective on November 16, 2016. The offer and sale of the shares of Common Stock in the Offering are described in the Company’s prospectus constituting a part of the Registration Statement, as supplemented by a final prospectus supplement dated November 16, 2016.

On November 21, 2016, the Company issued a press release (the “Press Release”) announcing the closing of the Offering. A copy of the Press Release is attached hereto as Exhibit 99.1 and is incorporated herein by reference.

Pursuant to the rules and regulations of the Securities and Exchange Commission, the information in this Item 7.01 disclosure, including Exhibit 99.1 and the information set forth therein, is deemed to have been furnished and shall not be deemed to be “filed” under the Exchange Act.

See Exhibit Index immediately following signature page.

SIGNATURE

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.

EXHIBIT INDEX