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: November 7, 2013 (Date of earliest event reported)

Rosetta Resources Inc.

(Exact name of registrant as specified in its charter)

713-335-4000

(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:

Underwriting Agreement

On November 7, 2013, Rosetta Resources Inc. (the “Company”) and certain subsidiary guarantors of the Company (the “Guarantors”) entered into an underwriting agreement with Wells Fargo Securities, LLC, as representative of the several underwriters named therein, with respect to the public offering by the Company of $600,000,000 in aggregate principal amount of 5.875% Senior Notes due 2022 (the “Notes”). The Notes have been registered under the Securities Act of 1933, as amended (the “Securities Act”), pursuant to the Company’s Registration Statement on Form S-3 (File No. 333-180439), which became effective upon filing with the Securities and Exchange Commission (the “Commission”) on March 29, 2012 (the “Registration Statement”), and as supplemented by the prospectus supplement relating to the Notes filed with the Commission on November 12, 2013. The Company intends to use the net proceeds from the offering of approximately $590.3 million, after deducting the underwriting discount and estimated offering expenses, to repay all of the borrowings outstanding under its revolving credit facility and for general corporate purposes.

The underwriting agreement contains customary representations, warranties and agreements by the Company and Guarantors, including obligations of the Company and Guarantors to indemnify the underwriters for certain liabilities under the Securities Act. 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 to this Current Report on Form 8-K.

Relationships

In the ordinary course of their various business activities, the underwriters and their respective affiliates may make or hold a broad array of investments, including serving as counterparties to certain derivative and hedging arrangements, and actively trade debt and equity securities (or related derivative securities) and financial instruments (including bank loans) for their own account and for the accounts of their customers, and may have in the past and at any time in the future, hold long and short positions in such securities and instruments. Such investment and securities activities may have involved, and in the future may involve, the Company’s securities and instruments. The underwriters and their respective affiliates may also make investment recommendations and/or publish or express independent research views in respect of such securities or instruments and may at any time hold, or recommend to clients that they acquire, long and/or short positions in such securities and instruments. An affiliate of Wells Fargo Securities, LLC serves as administrative agent under the Company’s revolving credit facility. Additionally, affiliates of certain of the underwriters serve as lenders under the Company’s revolving credit facility, and, as such, will receive a portion of the proceeds from the offering from the repayment of borrowings under such facility. An affiliate of Wells Fargo Securities, LLC also serves as the trustee for the Company’s existing notes and will serve as the trustee for the Notes.

(d) Exhibits.

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.

EXHIBIT INDEX