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):

May 22, 2013

INFINERA CORPORATION

(Exact name of registrant as specified in its charter)

140 Caspian Court

Sunnyvale, CA 94089

(Address of principal executive offices, including zip code)

(408) 572-5200

(Registrant’s telephone number, including area code)

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 May 23, 2012, Infinera Corporation (the “Company”), entered into a purchase agreement (the “Purchase Agreement”) with Morgan Stanley & Co. LLC and Goldman, Sachs & Co., as representatives of the several initial purchasers named therein (collectively, the “Initial Purchasers”), to issue and sell $135 million aggregate principal amount of 1.75% Convertible Senior Notes due 2018 (the “Notes”) in a private placement to qualified institutional buyers pursuant to Rule 144A under the Securities Act of 1933, as amended (the “Securities Act”). In addition, the Company granted the Initial Purchasers a 30-day option to purchase up to an additional $15 million aggregate principal amount of the Notes on the same terms and conditions to cover overallotments, if any.

The Purchase Agreement includes customary representations, warranties and covenants by the Company and customary closing conditions. Under the terms of the Purchase Agreement, the Company has agreed to indemnify the Initial Purchasers against certain liabilities.

The description of the Purchase Agreement contained herein is qualified in its entirety by reference to the Purchase Agreement attached as Exhibit 10.1 to this Current Report on Form 8-K and is incorporated herein by reference.

On May 22, 2013, the Company issued a press release announcing its intention to offer the Notes in a private placement to qualified institutional buyers pursuant to Rule 144A under the Securities Act. A copy of this press release is filed herewith as Exhibit 99.1 and is incorporated herein by reference.

On May 23, 2013, the Company issued a press release annoucing the pricing of its offering of $135 million aggregate principal amount of the Notes in a private placement to qualified institutional buyers pursuant to Rule 144A under the Securities Act. A copy of this press release is filed herewith as Exhibit 99.2 and is incorporated herein by reference.

(d) Exhibits

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.

EXHIBIT INDEX