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): June 6, 2013

LIMELIGHT NETWORKS, INC.

(Exact name of Registrant as specified in its charter)

222 South Mill Avenue, 8^th Floor

Tempe, AZ 85281

(Address, including zip code, of principal executive offices)

(602) 850-5000

(Registrant’s telephone number, including area code)

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):

On April 9, 2013, Limelight Networks, Inc. (the “Company”) announced in a current report on Form 8-K that Nathan F. Raciborski expressed his intent to the Board of Directors (the “Board”) not to stand for re-election as a Class II director of the Company at the 2013 Annual Meeting of Stockholders. The Company also announced that the Board unanimously approved a reduction in the size of the Board from nine seats to eight seats, effective as of the Annual Meeting. On June 6, 2013, the Company held its Annual Meeting, and following this meeting, the Board was reduced from nine members to eight members, consisting of three Class I directors, two Class II directors and three Class III directors.

On June 6, 2013, the Company held its annual meeting of stockholders. At the annual meeting, the following matters were submitted to the vote of the stockholders, with the results of voting on each such matter as set forth below:

Proposal 1: The Company’s stockholders approved a proposal to re-elect the following three Class III directors to the Company’s Board of Directors, each to hold office until the 2016 annual meeting of stockholders (and until each such director’s successor shall have been duly elected and qualified), with voting results as follows:

Proposal 2: The Company’s stockholders approved a proposal to ratify the appointment of Ernst & Young LLP as its independent registered public accounting firm for the fiscal year ending December 31, 2013, with voting results as follows:

Proposal 3: The Company’s stockholders approved a proposal to approve the Company’s 2013 Employee Stock Purchase Plan, with voting results as follows:

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.