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): November 19, 2014

ONEOK Partners, L.P.

(Exact name of registrant as specified in its charter)

100 West Fifth Street; Tulsa OK

(Address of principal executive offices)

74103-4298

(Zip code)

(918) 588-7000

(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 November 19, 2014, ONEOK Partners, L.P., a Delaware limited partnership (the “Partnership”), entered into an Equity Distribution Agreement (the “Agreement”) with Citigroup Global Markets Inc., Barclays Capital Inc., Merrill Lynch, Pierce, Fenner & Smith Incorporated, Deutsche Bank Securities Inc., Goldman, Sachs & Co., Jefferies LLC, J.P. Morgan Securities LLC, Morgan Stanley & Co. LLC, Mitsubishi UFJ Securities (USA), Inc., RBC Capital Markets, LLC, UBS Securities LLC and Wells Fargo Securities, LLC (each, a “Manager” and, collectively, the “Managers”). Pursuant to the terms of the Agreement, the Partnership may issue and sell from time to time through the Managers, the Partnership’s common units representing limited partner interests having an aggregate offering price of up to $650,000,000 (the “Common Units”). Sales of the Common Units, if any, will be made by means of ordinary brokers’ transactions through the facilities of the New York Stock Exchange at market prices, in block transactions, or as otherwise agreed by the Partnership and the Managers, by means of any other existing trading market for the Common Units or to or through a market maker other than on an exchange.

Under the terms of the Agreement, the Partnership may also sell Common Units to one or more of the Managers as principal for their own account at a price to be agreed upon at the time of sale. Any sale of Common Units to a Manager as principal would be pursuant to the terms of a separate terms agreement between the Partnership and such Manager.

The Partnership intends to use the net proceeds from any sales pursuant to the Agreement, after deducting Managers’ commissions and the Partnership’s offering expenses, for general partnership purposes, which may include repaying or refinancing all or a portion of the Partnership’s outstanding indebtedness and funding working capital, capital expenditures or acquisitions.

The Common Units will be issued pursuant to the Partnership’s existing effective shelf registration statement on Form S-3 (Registration No. 333-198313).

The Agreement contains customary representations, warranties and agreements by the Partnership, indemnification obligations of the Partnership and the Managers, including for liabilities under the Securities Act of 1933, other obligations of the parties and termination provisions. The foregoing description of the Agreement does not purport to be complete and is qualified in its entirety by reference to the full text of the Agreement, a copy of which is filed herewith as Exhibit 1.1 and is incorporated by reference herein. Legal opinions relating to the Common Units are filed herewith as Exhibits 5.1 and 8.1.

(d) Exhibits

1

SIGNATURES

Pursuant to the requirements of the Securities Exchange Act of 1934, as amended, the registrant has duly caused this report to be signed on its behalf by the undersigned hereunto duly authorized.

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Exhibit Index

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