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) March 11, 2013

Matador Resources Company

(Exact name of registrant as specified in its charter)

Registrant’s telephone number, including area code: (972) 371-5200

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 September 28, 2012, Matador Resources Company (the “Company”), as a guarantor, and MRC Energy Company, its wholly-owned subsidiary, as borrower, entered into an amended and restated senior secured revolving credit agreement (the “Prior Credit Agreement”). For a summary of key terms of the Prior Credit Agreement, see Item 1.01 of the Company’s Current Report on Form 8-K filed on October 4, 2012, which description is incorporated herein by reference. On March 11, 2013, MRC Energy Company, as borrower, entered into an amendment (the “Amendment”) to the Prior Credit Agreement (as amended, the “Credit Agreement”) and the Company reaffirmed its guaranty of MRC Energy Company’s obligations under the Credit Agreement. The Amendment increased the borrowing base from $215 million to $255 million based on the lenders’ review of the Company’s proved oil and natural gas reserves at December 31, 2012. The conforming borrowing base was also increased from $180 million to $220 million. Among other things, the Amendment also provided for the inclusion of Capital One, N.A., BMO Harris Financing, Inc. (Bank of Montreal) and IBERIABANK in the Company’s lending group, joining Royal Bank of Canada, as administrative agent, Comerica Bank, Citibank, N.A., The Bank of Nova Scotia and SunTrust Bank. The Amendment also delayed the first measurement of the current ratio from March 31, 2013 to March 31, 2014.

In the ordinary course of their respective businesses, certain of the lenders or their affiliates have in the past performed, and may in the future from time to time perform, investment banking, advisory, lending and/or commercial banking or other financial services for the Company for which they received, or may receive, customary fees and reimbursement of expenses.

Attached hereto as Exhibit 99.1 is a press release (the “Press Release”) issued by the Company on March 13, 2013, announcing its financial results for the three month and twelve month periods ended December 31, 2012. The Press Release includes an operational update for the first quarter of 2013. The Press Release is incorporated by reference into this Item 2.02, and the foregoing description of the Press Release is qualified in its entirety by reference to this exhibit.

The information furnished pursuant to this Item 2.02, including Exhibit 99.1, shall not be deemed to be “filed” for the purposes of Section 18 of the Securities Exchange Act of 1934, as amended (the “Exchange Act”), and will not be incorporated by reference into any filing under the Securities Act of 1933, as amended (the “Securities Act”), unless specifically identified therein as being incorporated therein by reference.

In the Press Release, the Company has included as “non-GAAP financial measures,” as defined in Item 10 of Regulation S-K of the Exchange Act, (i) earnings before interest expense, income taxes, depletion, depreciation and amortization, accretion of asset retirement obligations, property impairments, unrealized derivative gains and losses, certain other non-cash items and non-cash stock-based compensation expense, including stock option and grant expense and restricted stock and restricted stock unit expense, and net gain or loss on asset sales and inventory impairment (“Adjusted EBITDA”) and (ii) present value discounted at 10% (pre-tax) of estimated total proved reserves (“PV-10”). In the Press Release, the Company has provided reconciliations of the non-GAAP financial measures to the most directly comparable financial measures calculated and presented in accordance with generally-accepted accounting principles (“GAAP”) in the United States. In addition, in the Press Release, the Company has provided the reasons why the Company believes those non-GAAP financial measures provide useful information to investors.

Item 1.01 above is incorporated herein by reference.

Item 2.02 above is incorporated herein by reference.

The information furnished pursuant to this Item 7.01, including Exhibit 99.1, shall not be deemed to be “filed” for the purposes of Section 18 of the Exchange Act and will not be incorporated by reference into any filing under the Securities Act unless specifically identified therein as being incorporated therein by reference.

(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