UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, DC 20549

FORM 8-K

CURRENT REPORT

PURSUANT TO SECTION 13 OR 15(d)

OF THE SECURITIES EXCHANGE ACT OF 1934

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 (see General Instruction A.2. below):

The Special Meeting of Stockholders (the “Special Meeting”) of Fuel Systems Solutions, Inc. (the “Company”) was held at 12:00 p.m., Eastern Time, on Tuesday, May 31, 2016 at the offices of Day Pitney LLP, 7 Times Square, 20th Floor, New York, New York 10036. As of April 29, 2016, the record date for the Special Meeting, there were 18,094,043 shares of common stock issued and outstanding. A quorum of 14,260,026 shares of common stock was present or represented at the Special Meeting.

The stockholders voted on the following proposals and cast their votes as follows:

1. Stockholders approved the merger and adopted the merger agreement, dated as of September 1, 2015, by and among Westport Innovations Inc., Whitehorse Merger Sub Inc. and the Company, as amended by amendment no. 1 thereto, dated March 6, 2016, as set forth below:

2. Stockholders approved amendments to awards of restricted stock issued to the Company’s non-employee directors providing that the vesting date shall be the earlier of the vesting date set forth in the award or a change in control of the Company, as set forth below:

3. Stockholders approved, on an advisory (non-binding) basis, payments that will or may be paid by the Company to its named executive officers in connection with the merger, as set forth below:

Since there were sufficient votes represented at the Special Meeting to approve the merger and adopt the merger agreement, the proposal to adjourn the Special Meeting to solicit additional proxies was moot and therefore not presented or reported on.

A copy of the press release issued by the Company announcing that the stockholders approved the merger with Westport is included as Exhibit 99.1 hereto.

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.