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): April 14, 2015

RTI SURGICAL, INC.

(Exact name of registrant as specified in its charter)

Registrant’s telephone number, including area code: (386) 418-8888

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:

On April 14, 2015, RTI Surgical, Inc. held the 2015 Annual Meeting. All matters submitted to a vote of the Company’s stockholders as described in the proxy statement furnished to stockholders in connection with the annual meeting, which was filed with the Securities and Exchange Commission on March 9, 2015, were approved. The number of shares of common stock entitled to vote at the annual meeting was 68,726,845. The number of shares of common stock present or represented by valid proxy was 51,042,563. At the 2015 Annual Meeting, the Company’s stockholders took the following actions:

1. Election of Directors — Stockholders elected five Class I directors, Dean H. Bergy, Philip R. Chapman, Peter F. Gearen, M.D., Adrian J. R. Smith and Shirley A. Weis, to serve on the Company’s board of directors and hold office until the next annual meeting of stockholders or until their respective successors have been duly elected and qualified. The number of votes cast for each of these individuals is as set forth below:

2. To approve and adopt the RTI Surgical, Inc. 2015 Incentive Compensation Plan — Stockholders approved and adopted the RTI Surgical, Inc. 2015 Incentive Compensation Plan as disclosed in the proxy statement. The vote totals for the approval and adoption of the RTI Surgical, Inc. 2015 Incentive Compensation Plan were 43,268,281 shares for, 5,054,775 shares against and 2,719,507 share abstentions.

3. Advisory Vote on Executive Compensation Program (the “Say on Pay Vote”) — Stockholders approved (on an advisory basis) the compensation of the Company’s named executive officers, as disclosed in the proxy statement. The vote totals for the Say on Pay Vote were 47,460,497 shares for, 850,222 shares against and 2,731,844 share abstentions.

Banks and brokers were not eligible to vote shares for which they did not receive instructions from the beneficial owners thereof on these proposals. The final report of the inspector of election indicated that there were no broker non-votes on any of these proposals.

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.