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 2, 2017

SPECTRA ENERGY PARTNERS, LP

(Exact name of registrant as specified in its charter)

Registrant’s Telephone Number, Including Area Code: (713) 627-5400

Not Applicable

Former name or former address, if changed since last report

Check the appropriate box below if the Form 8-K is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions:

Indicate by check mark whether the registrant is an emerging growth company as defined in Rule 405 of the Securities Act of 1933 (17 CFR 230.405) or Rule 12b-2 of the Securities Exchange Act of 1934 (17 CFR 240.12b-2).

Emerging growth company              ¨

If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 13(a) of the Exchange Act. ¨

Item 8.01 Other Events

On June 2, 2017, Spectra Energy Partners, LP (the “Partnership”) entered into an Underwriting Agreement (the “Underwriting Agreement”) with Merrill Lynch, Pierce, Fenner & Smith Incorporated relating to the public offering of $400 million aggregate principal amount of the Partnership’s floating rate senior notes due 2020 (the “Notes”) at a price to the public of 100% of the face amount of the Notes.

The offering of the Notes is expected to close on June 7, 2017. Net proceeds from the offering will be used to repay a portion of the Partnership’s term loan credit facility borrowings that are outstanding, for general partnership purposes or any combination of such purposes. The offering was made pursuant to the Partnership’s shelf registration statement on Form S-3 (File No. 333-197967), which became effective on August 8, 2014.

The Underwriting Agreement contains customary representations, warranties and agreements of the Partnership and certain affiliates, and customary conditions to closing, indemnification rights and termination provisions. The foregoing description of the Underwriting Agreement does not purport to be complete and is qualified in its entirety by reference to the full text of the Underwriting Agreement, which is filed as Exhibit 1.1 hereto and incorporated by reference herein. A legal opinion and computation of the ratio of earnings to fixed charges of the Partnership for the three-month period ended March 31, 2017 are filed herewith as Exhibit 5.1 and Exhibit 12.1, respectively.

Item 9.01 Financial Statements and 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