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As filed with the Securities and Exchange Commission on April 18, 2017

Registration No. 333-                

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, DC 20549

FORM S-3

REGISTRATION STATEMENT

UNDER

THE SECURITIES ACT OF 1933

GULFPORT ENERGY CORPORATION

(Exact Name of Registrant as Specified in Its Charter)

3001 Quail Springs Parkway

Oklahoma City, Oklahoma 73134

(405) 252-4600

(Address, Including Zip Code, and Telephone Number, Including Area Code, of Registrant’s Principal Executive Offices)

Michael G. Moore

Chief Executive Officer and President

3001 Quail Springs Parkway

Oklahoma City, Oklahoma 73134

(405) 252-4600

(Name, Address, Including Zip Code, and Telephone Number, Including Area Code, of Agent For Service)

Copies to:

Seth R. Molay, P.C.

Akin Gump Strauss Hauer & Feld LLP

1700 Pacific Avenue, Suite 4100

Dallas, TX 75201

(214) 969-2800

(214) 969-4343 (facsimile)

Approximate date of commencement of proposed sale to the public: From time to time after this Registration Statement becomes effective.

If the only securities being registered on this form are being offered pursuant to dividend or interest reinvestment plans, please check the following box.  ☐

If any of the securities being registered on this form are to be offered on a delayed or continuous basis pursuant to Rule 415 under the Securities Act of 1933, other than securities offered only in connection with dividend or interest reinvestment plans, check the following box.  ☒

If this form is filed to register additional securities for an offering pursuant to Rule 462(b) under the Securities Act, please check the following box and list the Securities Act registration statement number of the earlier effective registration statement for the same offering.  ☐

If this form is a post-effective amendment filed pursuant to Rule 462(c) under the Securities Act, check the following box and list the Securities Act registration statement number of the earlier effective registration statement for the same offering.  ☐

If this form is a registration statement pursuant to General Instruction I.D. or a post-effective amendment thereto that shall become effective upon filing with the Commission pursuant to Rule 462(e) under the Securities Act, check the following box.  ☒

If this Form is a post-effective amendment to a registration statement filed pursuant to General Instruction I.D. filed to register additional securities or additional classes of securities pursuant to Rule 413(b) under the Securities Act, check the following box.  ☐

Indicate by check mark whether the registrant is a large accelerated filer, an accelerated filer, a non-accelerated filer, a smaller reporting company, or an emerging growth company. See the definitions of “large accelerated filer,” “accelerated filer” “smaller reporting company,” and “emerging growth company” in Rule 12b-2 of the Exchange Act. (Check one):

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 7(a)(2)(B) of the Securities Act.  ☐

CALCULATION OF REGISTRATION FEE

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Prospectus

Common Stock

By this prospectus, we may offer and sell our common stock from time to time in one or more offerings. This prospectus may also be used by the selling stockholder named in this prospectus and any other selling stockholders that may be identified in any applicable prospectus supplement in connection with resales, from time to time in one or more offerings, of up to 23,852,117 shares of our common stock held by such selling stockholders. We refer to our common stock that may be offered by us and/or selling stockholders pursuant to this prospectus and any applicable prospectus supplement collectively as the “common stock.”

This prospectus provides you with a general description of the common stock and the general manner in which we or the selling stockholders will offer the common stock. Each time we or the selling stockholders sell common stock, to the extent required, we will provide a supplement to this prospectus that contains specific information about the offering. The supplement may also add, update or change information contained in this prospectus. You should carefully read this prospectus, all prospectus supplements and all other documents incorporated by reference in this prospectus before you invest in our common stock.

Investing in our common stock involves risks. See “Risk Factors” beginning on page 1.

Our common stock is listed on The NASDAQ Global Select Market under the symbol “GPOR.” Our principal executive offices are located at 3001 Quail Springs Parkway, Oklahoma City, Oklahoma 73134, and our telephone number is (405) 252-4600.

Neither the Securities and Exchange Commission nor any state securities commission has approved or disapproved of this common stock or determined if this prospectus is truthful or complete. Any representation to the contrary is a criminal offense.

The date of this prospectus is April 18, 2017.

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ABOUT THIS PROSPECTUS

This prospectus is part of a “shelf” registration statement that we filed with the Securities and Exchange Commission, or SEC, as a “well-known seasoned issuer” (as defined in Rule 405 of the Securities Act of 1933, as amended, or the Securities Act) using a “shelf” registration process. Under this shelf registration process, we may, from time to time, offer and/or sell any combination of the common stock described in this prospectus, and the selling stockholders named in this prospectus or selling stockholders that may be identified in an applicable prospectus supplement, may, from time to time, resell up to 23,852,117 shares of our common stock, in each case in one or more offerings. This prospectus provides you with a general description of the common stock we and/or selling stockholders may offer. This prospectus does not contain all the information set forth in the registration statement as permitted by the rules of the SEC. Each time we or selling stockholders sell common stock, to the extent required, we will provide a supplement to this prospectus that will contain specific information about the terms of that offering. That prospectus supplement may also add, update or change information contained in this prospectus. Before purchasing any common stock, you should carefully read both this prospectus and any applicable prospectus supplement, together with the additional information described in this prospectus under the headings “Where You Can Find More Information” and “Information Incorporated by Reference.”

You should rely only on the information contained in this prospectus and in any applicable prospectus supplement, including any information incorporated by reference. Neither we nor the selling stockholder have authorized any other person to provide you with different information. If anyone provides you with different or inconsistent information, you should not rely on it. You should not assume that the information appearing in this prospectus, any prospectus supplement or any document incorporated by reference is accurate at any date other than as of the date of each such document. Our business, financial condition, results of operations and prospects may have changed since the date indicated on the cover page of such documents.

The distribution of this prospectus may be restricted by law in certain jurisdictions. You should inform yourself about and observe any of these restrictions. This prospectus does not constitute, and may not be used in connection with, an offer or solicitation by anyone in any jurisdiction in which the offer or solicitation is not authorized, or in which the person making the offer or solicitation is not qualified to do so, or to any person to whom it is unlawful to make the offer or solicitation.

When used in this prospectus or in any supplement to this prospectus, the terms “Gulfport,” the “Company,” “we,” “our” and “us” refer to Gulfport Energy Corporation and its subsidiaries, unless otherwise indicated or the context otherwise requires.

CAUTIONARY NOTE REGARDING FORWARD-LOOKING STATEMENTS

This prospectus and the documents incorporated by reference into this prospectus may include “forward-looking statements” within the meaning of Section 27A of the Securities Act and Section 21E of the Securities Exchange Act of 1934, as amended, or the Exchange Act. These statements involve known and unknown risks, uncertainties and other factors that may cause our actual results, performance or achievements to be materially different from any future results, performance or achievements expressed or implied by the forward-looking statements. In some cases, you can identify forward-looking statements by terms such as “may,” “will,” “should,” “could,” “would,” “expects,” “plans,” “anticipates,” “intends,” “believes,” “estimates,” “projects,” “predicts,” “potential” and similar expressions intended to identify forward-looking statements. All statements, other than statements of historical facts, included in this prospectus and the documents incorporated by reference into this prospectus that address activities, events or developments that we expect or anticipate will or may occur in the future, including such things as estimated future net revenues from oil and gas reserves, future capital expenditures (including the amount and nature thereof), drilling activity, production, expenses, business strategy and measures to implement strategy, competitive strengths, goals, expansion and growth of our business and operations, plans, references to future success, references to intentions as to future matters and other such matters

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are forward-looking statements. These statements are based on certain assumptions and analyses made by us in light of our experience and our perception of historical trends, current conditions and expected future developments as well as other factors we believe are appropriate in the circumstances. However, whether actual results and developments will conform with our expectations and predictions is subject to a number of risks and uncertainties, including those discussed under the heading “Risk Factors” in this prospectus and in any prospectus supplement and those discussed in the documents incorporated by reference into this prospectus. Consequently, all of the forward-looking statements made in this prospectus, and the documents incorporated by reference into this prospectus and any prospectus supplement, are qualified by these cautionary statements and we cannot assure you that the actual results or developments anticipated by us will be realized or, even if realized, that they will have the expected consequences to or effects on us, our business or operations. We have no intention, and disclaim any obligation, to update or revise any forward-looking statements, whether as a result of new information, future results or otherwise.

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OUR COMPANY

We are an independent oil and natural gas exploration and production company focused on the exploration, exploitation, acquisition and production of natural gas, crude oil and natural gas liquids in the United States. Our corporate strategy is to internally identify prospects, acquire lands encompassing those prospects and evaluate those prospects using subsurface geology and geophysical data and exploratory drilling. Using this strategy, we have developed an oil and natural gas portfolio of proved reserves, as well as development and exploratory drilling opportunities on high potential conventional and unconventional oil and natural gas prospects. Our principal properties are located in the Utica Shale primarily in Eastern Ohio and along the Louisiana Gulf Coast in the West Cote Blanche Bay, or WCBB, and Hackberry fields. In February 2017, we acquired 46,000 net surface acres with multiple producing zones, including the Woodford and Springer formations, in Grady, Stephens, and Garvin counties, Oklahoma. In addition, we have an interest in producing properties in the Niobrara Formation of Northwestern Colorado and the Bakken Formation. We also hold a significant acreage position in the Alberta oil sands in Canada through our interest in Grizzly Oil Sands ULC, or Grizzly, and an interest in an entity that operates in the Phu Horm gas field in Thailand. We also hold an approximate 24.2% equity interest in Mammoth Energy Services, Inc., or Mammoth Energy, an oil field services company listed on the NASDAQ Global Select Market. We seek to achieve reserve growth and increase our cash flow through our annual drilling programs.

Our principal executive offices are located at 3001 Quail Springs Parkway, Oklahoma City, Oklahoma 73134, and our telephone number is (405) 252-4600. Our website address is www.gulfportenergy.com. Information contained on our website does not constitute a part of this prospectus or any prospectus supplement.

RISK FACTORS

Investment in our common stock involves certain risks. You should carefully consider the factors contained in our Annual Report on Form 10-K for the fiscal year ended December 31, 2016 under the headings “Risk Factors” and “Management’s Discussion and Analysis of Financial Condition and Results of Operations—Critical Accounting Policies and Estimates” and in any other filings we made with the SEC prior to the filing of this prospectus, including those incorporated by reference into this prospectus, under the heading “Risk Factors” before investing in our common stock. You should also consider similar information contained in any annual report on Form 10-K, quarterly reports on Form 10-Q, current reports on Form 8-K or other document filed by us with the SEC after the date of this prospectus before deciding to invest in our common stock. We will also include in any prospectus supplement a description of any other risk factors applicable to an offering contemplated by such prospectus supplement. Additional risks and uncertainties not known to us or that we view as immaterial may also impair our business operations. Any of these risks could materially and adversely affect our business, financial condition, results of operations and cash flows and could result in a loss of all or part of your investment.

USE OF PROCEEDS

Unless the applicable prospectus supplement indicates otherwise, we intend to use the net proceeds from the sale of the common stock for general corporate purposes, including without limitation repaying or refinancing all or a portion of our existing short-term and long-term debt, making acquisitions of assets, businesses or securities, capital expenditures and for working capital. The precise amount and timing of the application of such proceeds will depend upon our funding requirements and the availability and cost of other capital. Pending any specific application of the net proceeds, we intend to invest our net proceeds in short-term, investment-grade securities, interest-bearing securities or guaranteed obligations of the United States or its agencies.

We will not receive any proceeds from the sale of any shares of common stock by the selling stockholder, unless we otherwise indicate in any applicable prospectus supplement.

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SELLING STOCKHOLDERS

The shares of our common stock covered by this prospectus are being offered by the selling stockholder listed in the table below. This prospectus will not cover subsequent sales of common stock purchased from the selling stockholder named in this prospectus. An aggregate amount of 23,852,117 shares of our common stock were issued to the selling stockholder on February 17, 2017, as partial consideration for the acquisition of certain assets of the selling stockholder. In connection with the consummation of this acquisition, we entered into a Registration Rights Agreement (the “Registration Rights Agreement”) with the selling stockholder, which granted the selling stockholder and its transferees registration rights with respect to the shares of our common stock issued to the selling stockholder, and we are fulfilling those registration requirements by registering the 23,852,117 shares of our common stock covered by this prospectus. As used herein, the term “selling stockholder” includes the stockholder listed in the table below and its transferees. Pursuant to the Registration Rights Agreement, we will pay all expenses relating to the registration and offering of these shares, except that the selling stockholder will pay any underwriting discounts or commissions. Pursuant to the terms of the Registration Rights Agreement, we agreed to indemnify the selling stockholder against certain liabilities, including liabilities under the Securities Act, and the selling stockholder has agreed to indemnify us against certain liabilities, including liabilities under the Securities Act, which may arise from any written information furnished to us by the selling stockholder specifically for use in this prospectus.

No offer or sale under this prospectus may be made by a stockholder unless that stockholder is listed in the table below, in a supplement to this prospectus or in an amendment to the related registration statement that has become effective. We may supplement or amend this prospectus to include additional selling stockholders upon provision of all required information to us and subject to the terms of the Registration Rights Agreement.

The following table sets forth the maximum number of shares of our common stock that may be sold by the selling stockholder. We cannot predict when or in what amount the selling stockholder may sell any of the shares offered by the selling stockholder in this prospectus, if at all. The table also sets forth the name of the selling stockholder, the nature of any position, office, or other material relationship which the selling stockholder has had, within the past three years, with us or with any of our predecessors or affiliates, and the number of shares of our common stock to be owned by the selling stockholder after completion of the offering. We are filing the registration statement of which this prospectus is a part pursuant to contractual obligations with the selling stockholder, as described in more detail below. We will pay all expenses relating to the registration of the shares by the selling stockholder under the Securities Act and any other offering expenses, except that the selling stockholder will pay any underwriting discounts or commissions.

We prepared the table based on information provided to us by the selling stockholder. We have not sought to verify such information. Additionally, the selling stockholder may have sold or transferred some or all of its shares of our common stock in transactions exempt from the registration requirements of the Securities Act since the date on which the information in the table was provided to us. Other information about the selling stockholder may also change over time.

Except as otherwise indicated, the selling stockholder has sole voting and dispositive power with respect to such shares.

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DESCRIPTION OF CAPITAL STOCK

The following summary description of our capital stock is qualified in its entirety by reference to our restated certificate of incorporation, or our certificate of incorporation, and our amended and restated bylaws, or our bylaws, each of which is incorporated by reference in this prospectus.

Common Stock

We are currently authorized to issue up to 200,000,000 shares of common stock, par value $0.01 per share, of which there were 182,835,801 shares outstanding as of March 31, 2017, excluding 871,518 shares of unvested restricted stock awarded under our 2013 Restated Stock Incentive Plan. Holders of our common stock are entitled to cast one vote for each share held of record on each matter submitted to a vote of stockholders. There is no cumulative voting for election of directors. Subject to the prior rights of any series of preferred stock which may from time to time be outstanding, if any, holders of our common stock are entitled to receive ratably dividends when, as and if declared by the board of directors out of funds legally available for such purpose and, upon the liquidation, dissolution or winding up of the company, are entitled to share ratably in all assets remaining after payment of liabilities and payment of accrued dividends and liquidation preferences on the preferred stock, if any. There are no redemption or sinking fund provisions that are applicable to our common stock. Subject only to the requirements of the DGCL, the board of directors may issue shares of our common stock without stockholder approval, at any time and from time to time, to such persons and for such consideration as the board of directors deems appropriate. Holders of our common stock have no preemptive rights and have no rights to convert their common stock into any other securities. The outstanding common stock is validly authorized and issued, fully paid and nonassessable.

Preferred Stock

We are authorized to issue up to 5,000,000 shares of preferred stock, par value $0.01 per share. Shares of preferred stock may be issued from time to time in one or more series as the board of directors may from time to time determine, each of said series to be distinctively designated. The voting powers, preferences and relative, participating, optional and other special rights, and the qualifications, limitations or restrictions thereof, if any, of each such series of preferred stock may differ from those of any and all other series of preferred stock at any time outstanding, and, subject to certain limitations of our certificate of incorporation and the DGCL, the board of directors may fix or alter, by resolution or resolutions, the designation, number, voting powers, preferences and relative, participating, optional and other special rights, and qualifications, limitations and restrictions thereof, of each such series of preferred stock.

The issuance of any such preferred stock could adversely affect the rights of the holders of our common stock and therefore, reduce the value of the common stock. The ability of the board of directors to issue preferred stock could discourage, delay, or prevent a takeover of us. See “Risk Factors.”

Anti-takeover Effects of Provisions of Our Certificate of Incorporation and Our Bylaws

Some provisions of our certificate of incorporation and our bylaws contain provisions that could make it more difficult to acquire us by means of a merger, tender offer, proxy contest or otherwise, or to remove our incumbent officers and directors. These provisions, summarized below, are expected to discourage coercive takeover practices and inadequate takeover bids. These provisions are also designed to encourage persons seeking to acquire control of us to first negotiate with our board of directors. We believe that the benefits of increased protection of our potential ability to negotiate with the proponent of an unfriendly or unsolicited proposal to acquire or restructure us outweigh the disadvantages of discouraging such proposals because negotiation of such proposals could result in an improvement of their terms.

Preferred stock. Our certificate of incorporation permits our board of directors to authorize and issue one or more series of preferred stock, which may render more difficult or discourage an attempt to change control of us

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by means of a merger, tender offer, proxy contest or otherwise. For example, if in the due exercise of its fiduciary obligations, the board of directors were to determine that a takeover proposal is not in our best interest, the board of directors could cause shares of preferred stock to be issued without stockholder approval in one or more private offerings or other transactions that might dilute the voting or other rights of the proposed acquirer or insurgent stockholder or stockholder group.

Stockholder meetings. Our bylaws provide that a special meeting of stockholders may be called only by the Chairman of the Board, the Chief Executive Officer or by a resolution adopted by a majority of the total number of directors the board of directors would have if there were no vacancies.

Requirements for advance notification of stockholder nominations and proposals. Our bylaws and certificate of incorporation establish advance notice procedures with respect to stockholder proposals and the nomination of candidates for election as directors, other than nominations made by or at the direction of the board of directors.

Stockholder Action By Written Consent. Our bylaws provide that, except as may otherwise be provided with respect to the rights of the holders of preferred stock, no action that is required or permitted to be taken by our stockholders at any annual or special meeting may be effected by written consent of stockholders in lieu of a meeting of stockholders, unless the action to be effected by written consent of stockholders and the taking of such action by such written consent have expressly been approved in advance by our board of directors. This provision, which may not be amended by our stockholders except by the affirmative vote of holders of at least 66-2/3% of the voting power of all then outstanding shares of capital stock entitled to vote generally in the election of directors, voting together as a single class, makes it difficult for stockholders to initiate or effect an action by written consent that is opposed by our board of directors.

Amendment of the bylaws. Under Delaware law, the power to adopt, amend, alter or repeal bylaws is conferred upon the stockholders. A corporation may, however, in its certificate of incorporation also confer upon the board of directors the power to adopt, amend or repeal its bylaws. Our certificate of incorporation and bylaws grant our board of directors the power to adopt, amend, alter or repeal our bylaws at any regular or special meeting of the board of director on the affirmative vote of a majority of the total number of directors the board of directors would have if there were no vacancies. Our stockholders may adopt, amend, alter or repeal our bylaws but only at any regular or special meeting of stockholders by an affirmative vote of holders of at least 66-2/3% of the voting power of all then outstanding shares of capital stock entitled to vote generally in the election of directors, voting together as a single class.

The provisions of our certificate of incorporation and bylaws could have the effect of discouraging others from attempting hostile takeovers and, as a consequence, they may also inhibit temporary fluctuations in the market price of our common stock that often result from actual or rumored hostile takeover attempts. These provisions may also have the effect of preventing changes in our management. It is possible that these provisions could make it more difficult to accomplish transactions which stockholders may otherwise deem to be in their best interests.

Transfer Agent and Registrar

The transfer agent and registrar for our common stock is Computershare Trust Company, N.A.

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PLAN OF DISTRIBUTION

Initial Offering and Sale of Common Stock

We and the selling stockholder, which as used in this prospectus includes donees, pledgees, transferees or other successors-in-interest selling common stock received after the date of this prospectus from the selling stockholder as a gift, pledge, distribution or other transfer, may, from time to time, sell, transfer or otherwise dispose of any or all of the common stock offered by this prospectus or any applicable prospectus supplement on any stock exchange, market or trading facility on which such common stock are traded or in private transactions. These dispositions may be at fixed prices, at prevailing market prices at the time of sale, at prices related to the prevailing market price, at varying prices determined at the time of sale or at negotiated prices.

We and the selling stockholder may use any one or more of the following methods when disposing of the offered common stock:

The selling stockholder also may resell all or a portion of the common stock in open market transactions in reliance upon Rule 144 under the Securities Act.

If underwriters are used to sell the common stock, we and the selling stockholder, if any, will enter into an underwriting agreement or similar agreement with them at the time of the sale to them. In that event, underwriters may receive compensation from us and the selling stockholder, if any, in the form of underwriting discounts or commissions and may also receive commissions from purchasers of the common stock for whom they may act as agent.

To the extent required by applicable law, a prospectus supplement relating to the common stock will set forth:

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The common stock may be offered to the public either through underwriting syndicates represented by one or more managing underwriters or directly by one or more of such firms. Unless otherwise set forth in an applicable prospectus supplement, the obligations of underwriters or dealers to purchase the common stock will be subject to certain conditions precedent and the underwriters or dealers will be obligated to purchase all the common stock if any are purchased. Any public offering price and any discounts or concessions allowed or reallowed or paid by underwriters or dealers to other dealers may be changed from time to time.

In connection with sales of the shares of common stock under this prospectus, the selling stockholder may enter into hedging transactions with broker-dealers, who may in turn engage in short sales of the shares of common stock in the course of hedging the positions they assume. The selling stockholder also may sell shares of common stock short and deliver them to close out the short positions or loan or pledge the shares of common stock to broker-dealers that in turn may sell them.

The selling stockholder and any underwriters, dealers or agents that are involved in selling the common stock may be deemed to be “underwriters” within the meaning of the Securities Act in connection with such sales. In such event, any commissions received by them and any profit on the resale of the common stock purchased by them may be deemed to be underwriting commissions or discounts under the Securities Act.

In order to comply with the securities laws of some states, the shares sold in those jurisdictions may only be sold through registered or licensed brokers or dealers. In addition, in some states, the shares may not be sold unless the shares have been registered or qualified for sale in that state or an exemption from registration or qualification is available and is complied with.

The common stock may be sold directly by us, the selling stockholder or through agents designated by us from time to time. Any agent involved in the offer or sale of the common stock in respect of which this prospectus and a prospectus supplement is delivered will be named, and any commissions payable by us or the selling stockholder to such agent will be set forth, in any required prospectus supplement. Unless otherwise indicated in the prospectus supplement, any such agent will be acting on a best efforts basis for the period of its appointment.

If so indicated in the prospectus supplement, we or the selling stockholder will authorize underwriters, dealers or agents to solicit offers from certain specified institutions to purchase common stock from us or the selling stockholder at the public offering price set forth in the prospectus supplement pursuant to delayed delivery contracts providing for payment and delivery on a specified date in the future. Such contracts will be subject to any conditions set forth in the prospectus supplement and the prospectus supplement will set forth the commissions payable for solicitation of such contracts. The underwriters and other persons soliciting such contracts will have no responsibility for the validity or performance of any such contracts.

Underwriters, dealers and agents may be entitled under agreements entered into with us or the selling stockholder to be indemnified by us against certain civil liabilities, including liabilities under the Securities Act, or to contribution by us to payments which they may be required to make. The terms and conditions of such

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indemnification will be described in an applicable prospectus supplement. Underwriters, dealers and agents may be customers of, engage in transactions with or perform services for us or the selling stockholder in the ordinary course of business.

Any underwriters to whom common stock are sold by us or the selling stockholder for public offering and sale may make a market in such common stock, but such underwriters will not be obligated to do so and may discontinue any market making at any time without notice. No assurance can be given as to the liquidity of the trading market for any common stock.

Certain persons participating in any offering of common stock may engage in transactions that stabilize, maintain or otherwise affect the price of the common stock offered. In connection with any such offering, the underwriters, dealers or agents, as the case may be, may purchase and sell common stock in the open market. These transactions may include overallotment and stabilizing transactions and purchases to cover syndicate short positions created in connection with the offering. Stabilizing transactions consist of certain bids or purchases for the purpose of preventing or retarding a decline in the market price of the common stock and syndicate short positions involve the sale by the underwriters, dealers or agents, as the case may be, of a greater number of common stock than they are required to purchase from us in the offering. The underwriters may also impose a penalty bid, whereby selling concessions allowed to syndicate members or other broker-dealers for the common stock sold for their account may be reclaimed by the syndicate if such common stock are repurchased by the syndicate in stabilizing or covering transactions. These activities may stabilize, maintain or otherwise affect the market price of the common stock, which may be higher than the price that might otherwise prevail in the open market, and if commenced, may be discontinued at any time. These transactions may be effected on The NASDAQ Global Select Market, in the over-the-counter market or otherwise. These activities will be described in more detail in the sections entitled “Plan of Distribution” or “Underwriting” in the applicable prospectus supplement.

To the extent required, this prospectus may be amended or supplemented from time to time to describe a specific plan of distribution. The place and time of delivery for the shares of common stock in respect of which this prospectus is delivered will be set forth in the accompanying prospectus supplement.

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WHERE YOU CAN FIND MORE INFORMATION

We have filed with the SEC a registration statement on Form S-3 under the Securities Act covering the common stock offered by this prospectus. This prospectus does not contain all of the information that you can find in that registration statement and its exhibits. Certain items are omitted from this prospectus in accordance with the rules and regulations of the SEC. For further information with respect to us and the common stock offered by this prospectus, reference is made to the registration statement and the exhibits filed with the registration statement. Statements contained in this prospectus as to the contents of any contract or other document referred to are not necessarily complete and in each instance such statement is qualified by reference to each such contract or document filed with or incorporated by reference as part of the registration statement. We file reports, proxy and information statements and other information with the SEC. You may read any materials we have filed with the SEC free of charge at the SEC’s Public Reference Room at 100 F Street, N.E., Washington, D.C. 20549. Copies of all or any part of these documents may be obtained from such office upon the payment of the fees prescribed by the SEC. The public may obtain information on the operation of the public reference room by calling the SEC at 1-800-SEC-0330. The SEC maintains an Internet site that contains reports, proxy and information statements and other information regarding registrants that file electronically with the SEC. The address of the site is http://www.sec.gov. The registration statement, including all exhibits thereto and amendments thereof, has been filed electronically with the SEC.

You can also find our SEC filings on our website at www.gulfportenergy.com. The information contained on our website or any other website is not incorporated by reference into this prospectus and does not constitute a part of this prospectus.

INFORMATION INCORPORATED BY REFERENCE

The SEC allows us to “incorporate by reference” into this prospectus the information we provide in other documents filed by us with the SEC. The information incorporated by reference is an important part of this prospectus and any prospectus supplement. Any statement contained in a document that is incorporated by reference in this prospectus is automatically updated and superseded if information contained in this prospectus and any prospectus supplement, or information that we later file with the SEC, modifies and replaces this information. We incorporate by reference the following documents that we have filed with the SEC:

In addition, we incorporate by reference the financial statements of Diamondback Energy, Inc., or Diamondback, that have been included on pages F-1 to F-54 in Diamondback’s Annual Report on Form 10-K (File No. 001-35700) filed with the SEC on February 20, 2015.

In addition, all documents filed by us with the SEC under Sections 13(a), 13(c), 14 or 15(d) of the Exchange Act (other than those furnished pursuant to Item 2.02 or Item 7.01 of Form 8-K, unless otherwise stated therein) after the date of this prospectus will be considered to be incorporated by reference into this prospectus and to be a part of this prospectus from the dates of the filing of such documents. Pursuant to General Instruction B of Form 8-K, any information submitted under Item 2.02, Results of Operations and Financial Condition, or Item 7.01, Regulation FD Disclosure, of Form 8-K is not deemed to be “filed” for the purpose of Section 18 of the Exchange Act, and we are not subject to the liabilities of Section 18 with respect to information submitted under Item 2.02 or Item 7.01 of Form 8-K. We are not incorporating by reference any information submitted under Item 2.02 or Item 7.01 of Form 8-K into any filing under the Securities Act or the Exchange Act or into this prospectus, unless otherwise indicated on such Form 8-K.

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We hereby undertake to provide without charge to each person, including any beneficial owner, to whom this prospectus is delivered, upon written or oral request of any such person, a copy of any or all of the information that has been or incorporated by reference into this prospectus (excluding exhibits, unless the exhibits are specifically incorporated). You may request a copy of this prospectus or any of the incorporated documents at no charge to you by writing to Gulfport Energy Corporation, Attention: Investor Relations, at 3001 Quail Springs Parkway, Oklahoma City, Oklahoma 73134, or calling (405) 252-4600.

LEGAL MATTERS

Unless otherwise indicated in the applicable prospectus supplement, the validity of the common stock to be offered hereby offered by us and/or any selling stockholders will be passed upon by Akin Gump Strauss Hauer & Feld LLP. If legal matters in connection with offerings made by this prospectus are passed on by counsel for the underwriters, dealers or agents, if any, that counsel will be named in the applicable prospectus supplement.

EXPERTS

The audited consolidated financial statements and management’s assessment of the effectiveness of internal control over financial reporting incorporated by reference in this prospectus and elsewhere in the registration statement have been so incorporated by reference in reliance upon the reports of Grant Thornton LLP, independent registered public accountants, upon the authority of said firm as experts in accounting and auditing.

The audited historical financial statements of Vitruvian II Woodford, LLC included in exhibit 99.1 of Gulfport Energy Corporation’s Current Report on Form 8-K dated April 18, 2017 have been so incorporated in reliance on the report of PricewaterhouseCoopers LLP, independent accountants, given on the authority of said firm as experts in auditing and accounting.

Information incorporated by reference into this prospectus regarding estimates of our proved oil and natural gas reserves and the discounted present value of estimated future net revenue before income tax of our estimated proved reserves is based on reports prepared by (i) Netherland, Sewell & Associates, Inc. with respect to our Utica Shale acreage at December 31, 2016 and December 31, 2015 and our WCBB and Hackberry fields at each of December 31, 2016, 2015 and 2014, and our Niobrara field at December 31, 2015 and 2014, and (ii) Ryder Scott with respect to our Utica Shale acreage at December 31, 2014. All of such information has been incorporated by reference herein in reliance upon the authority of such firm as experts in such matters.

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PART II

INFORMATION NOT REQUIRED IN PROSPECTUS

Delaware Law

Section 145 of the Delaware General Corporation Law, or the DGCL, permits a corporation, under specified circumstances, to indemnify its directors, officers, employees or agents against expenses (including attorneys’ fees), judgments, fines and amounts paid in settlements actually and reasonably incurred by them in connection with any action, suit or proceeding brought by third parties by reason of the fact that they were or are directors, officers, employees or agents of the corporation, if such directors, officers, employees or agents acted in good faith and in a manner they reasonably believed to be in or not opposed to the best interests of the corporation and, with respect to any criminal action or proceeding, had no reasonable cause to believe their conduct was unlawful. In a derivative action, i.e., one by or in the right of the corporation, indemnification may be made only for expenses actually and reasonably incurred by directors, officers, employees or agents in connection with the defense or settlement of an action or suit, and only with respect to a matter as to which they shall have acted in good faith and in a manner they reasonably believed to be in or not opposed to the best interests of the corporation, except that no indemnification shall be made if such person shall have been adjudged liable to the corporation, unless and only to the extent that the court in which the action or suit was brought shall determine upon application that the defendant directors, officers, employees or agents are fairly and reasonably entitled to indemnity for such expenses despite such adjudication of liability.

We have adopted provisions in our bylaws and our certificate of incorporation which provide for indemnification of our officers and directors to the maximum extent permitted under the DGCL, as amended.

Certificate of Incorporation and Bylaws

Our certificate of incorporation, by reference to Section 102(b)(7) of the DGCL, provides that no director shall be personally liable to us or any of our stockholders for monetary damages resulting from breaches of their fiduciary duty as directors, except to the extent such limitation on or exemption from liability is not permitted under the DGCL. The effect of this provision of our certificate of incorporation is to eliminate our rights and those of our stockholders (through stockholders’ derivative suits on our behalf) to recover monetary damages against a director for breach of the fiduciary duty of care as a director, including breaches resulting from negligent or grossly negligent behavior, except, as restricted by the DGCL: (i) for any breach of the director’s

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duty of loyalty to the corporation or its stockholders; (ii) for acts or omissions not in good faith or which involve intentional misconduct or a knowing violation of law; (iii) in respect of certain unlawful dividend payments or stock redemptions or repurchases or (iv) for any transaction from which the director derived an improper personal benefit.

If the DGCL is amended to authorize corporate action further eliminating or limiting the liability of directors, then, in accordance with our certificate of incorporation, the liability of our directors to us or our stockholders will be eliminated or limited to the fullest extent authorized by the DGCL, as so amended. Any repeal or modification by our stockholders of provisions of our certificate of incorporation affecting indemnification rights will be prospective only, and will not in any way diminish or adversely affect any limitation on the personal liability of a director existing at the time of such repeal or modification.

Our bylaws provide that we will, to the fullest extent authorized or permitted by applicable law, as the same exists or may hereafter be amended, indemnify and hold harmless our current and former directors and officers, as well as those persons who, while directors or officers of our corporation, are or were serving as directors, officers, employees or agents of another entity, trust or other enterprise, including service with respect to an employee benefit plan, in connection with any threatened, pending or completed action, suit or proceeding, whether civil, criminal, administrative or investigative, against all expense, liability and loss (including, without limitation, attorney’s fees, judgments, fines, ERISA excise taxes and penalties and amounts paid in settlement) reasonably incurred or suffered by any such person in connection with any such proceeding. Notwithstanding the foregoing, a person eligible for indemnification pursuant to our bylaws will be indemnified by us in connection with a proceeding initiated by such person only if such proceeding was authorized by our board of directors, except for proceedings to enforce rights to indemnification.

The right to indemnification conferred by our bylaws is a contract right that includes the right to be paid by us the expenses (including, without limitation, attorney’s fees) incurred in defending or otherwise participating in any proceeding referenced above in advance of its final disposition, provided, however, that if the DGCL requires, an advancement of expenses incurred by any officer or director (solely in the capacity as an officer or director of our corporation) will be made only upon delivery to us of an undertaking, by or on behalf of such officer or director, to repay all amounts so advanced if it is ultimately determined by final judicial decision from which there is no further right to appeal that such person is not entitled to be indemnified for such expenses under our Certificate or otherwise.

The rights to indemnification and advancement of expenses will not be deemed exclusive of any other rights which any person covered by our bylaws may have or hereafter acquire under law, our Certificate, our bylaws, an agreement, vote of stockholders or disinterested directors, or otherwise.

Our bylaws include provisions relating to advancement of expenses and indemnification rights consistent with those set forth in our certificate of incorporation. In addition, our bylaws provide for a right of indemnitee to bring a suit in the event a claim for indemnification or advancement of expenses is not paid in full by us within a specified period of time. Our bylaws also permit us to purchase and maintain insurance, at our expense, to protect us and/or any director, officer, employee or agent of our corporation or another entity, trust or other enterprise against any expense, liability or loss, whether or not we would have the power to indemnify such person against such expense, liability or loss under the DGCL.

Any repeal or amendment of provisions of our bylaws affecting indemnification rights, whether by our stockholders or by changes in law, or the adoption of any other provisions inconsistent therewith, will (unless otherwise required by law) be prospective only, except to the extent such amendment or change in law permits us to provide broader indemnification rights on a retroactive basis, and will not in any way diminish or adversely affect any right or protection existing at the time of such repeal or amendment or adoption of such inconsistent provision with respect to any act or omission occurring prior to such repeal or amendment or adoption of such inconsistent provision. Our bylaws also permit us, to the extent and in the manner authorized or permitted by law, to indemnify and to advance expenses to persons other that those specifically covered by our Certificate.

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We maintain director and officer liability insurance providing insurance protection for specified liabilities under specified terms.

We may enter into an Underwriting Agreement in connection with a specific offering under which the underwriters will be obligated, under certain circumstances, to indemnify our directors and officers against certain liabilities, including liabilities under the Securities Act. Reference is made to the form of Underwriting Agreement to be filed as an Exhibit 1.1 or 1.2 to our Current Report on Form 8-K in connection with a specific offering.

The following is a list of exhibits filed as a part of this registration statement.

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(a) The undersigned registrant hereby undertakes:

(1) to file, during any period in which offers or sales are being made, a post-effective amendment to this registration statement:

(i) to include any prospectus required by Section 10(a)(3) of the Securities Act;

(ii) to reflect in the prospectus any facts or events arising after the effective date of this registration statement (or the most recent post-effective amendment thereof) which, individually or in the aggregate, represent a fundamental change in the information set forth in this registration statement. Notwithstanding the foregoing, any increase or decrease in volume of securities offered (if the total dollar value of securities offered would not exceed that which was registered) and any deviation from the low or high end of the estimated maximum offering range may be reflected in the form of prospectus filed with the SEC pursuant to Rule 424(b) under the Securities Act if, in the aggregate, the changes in volume and price represent no more than a 20% change in the maximum aggregate offering price set forth in the “Calculation of Registration Fee” table in the effective registration statement;

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(iii) to include any material information with respect to the plan of distribution not previously disclosed in this registration statement or any material change to such information in this registration statement;

provided, however, that subparagraphs (i), (ii) and (iii) do not apply if the information required to be included in a post-effective amendment by those subparagraphs is contained in periodic reports filed with or furnished to the SEC by the registrant pursuant to Section 13 or Section 15(d) of the Securities Exchange Act of 1934, as amended, or the Exchange Act, that are incorporated by reference in this registration statement, or is contained in a form of prospectus filed pursuant to Rule 424(b) of the Securities Act that is part of this registration statement.

(2) That, for the purpose of determining any liability under the Securities Act, each such post-effective amendment shall be deemed to be a new registration statement relating to the securities offered herein, and the offering of such securities at that time shall be deemed to be the initial bona fide offering thereof.

(3) To remove from registration by means of a post-effective amendment any of the securities being registered which remain unsold at the termination of the offering.

(4) That, for the purpose of determining liability under the Securities Act to any purchaser:

(i) Each prospectus filed by the registrant pursuant to Rule 424(b)(3) shall be deemed to be part of the registration statement as of the date the filed prospectus was deemed part of and included in the registration statement; and

(ii) Each prospectus required to be filed pursuant to Rule 424(b)(2), (b)(5), or (b)(7) as part of a registration statement in reliance on Rule 430B relating to an offering made pursuant to Rule 415(a)(1)(i), (vii), or (x) for the purpose of providing the information required by Section 10(a) of the Securities Act shall be deemed to be part of and included in the registration statement as of the earlier of the date such form of prospectus is first used after effectiveness or the date of the first contract of sale of securities in the offering described in the prospectus. As provided in Rule 430B, for liability purposes of the issuer and any person that is at that date an underwriter, such date shall be deemed to be a new effective date of the registration statement relating to the securities in the registration statement to which that prospectus relates, and the offering of such securities at that time shall be deemed to be the initial bona fide offering thereof. Provided, however, that no statement made in a registration statement or prospectus that is part of the registration statement or made in a document incorporated or deemed incorporated by reference into the registration statement or prospectus that is part of the registration statement will, as to a purchaser with a time of contract of sale prior to such effective date, supersede or modify any statement that was made in the registration statement or prospectus that was part of the registration statement or made in any such document immediately prior to such effective date; or

(5) That, for the purpose of determining liability of the registrant under the Securities Act to any purchaser in the initial distribution of the securities, the undersigned registrant undertakes that in a primary offering of securities of the undersigned registrant pursuant to this registration statement, regardless of the underwriting method used to sell the securities to the purchaser, if the securities are offered or sold to such purchaser by means of any of the following communications, the undersigned registrant will be a seller to the purchaser and will be considered to offer or sell such securities to such purchaser:

(i) Any preliminary prospectus or prospectus of the undersigned registrant relating to the offering required to be filed pursuant to Rule 424;

(ii) Any free writing prospectus relating to the offering prepared by or on behalf of the undersigned registrant or used or referred to by the undersigned registrant;

(iii) The portion of any other free writing prospectus relating to the offering containing material information about the undersigned registrant or its securities provided by or on behalf of the undersigned registrant; and

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(iv) Any other communication that is an offer in the offering made by the undersigned registrant to the purchaser.

(b) The undersigned registrant hereby undertakes that, for the purpose of determining any liability under the Securities Act, each filing of the registrant’s annual report pursuant to Section 13(a) or Section 15(d) of the Exchange Act that is incorporated by reference in this registration statement shall be deemed to be a new

registration statement relating to the securities offered therein, and the offering of such securities at that time shall be deemed to be the initial bona fide offering thereof.

(c) Insofar as indemnification for liabilities arising under the Securities Act may be permitted to directors, officers and controlling persons of the registrant, pursuant to the foregoing provisions or otherwise, the registrant has been advised that in the opinion of the Securities and Exchange Commission such indemnification is against public policy as expressed in the Securities Act and is, therefore, unenforceable. In the event that a claim for indemnification against such liabilities (other than the payment by the registrant of expenses incurred or paid by a director, officer or controlling person of the registrant in the successful defense of any action, suit or proceeding) is asserted by such director, officer or controlling person in connection with the securities being registered, the registrant will, unless in the opinion of its counsel the matter has been settled by controlling precedent, submit to a court of appropriate jurisdiction the question whether such indemnification by it is against public policy as expressed in the Securities Act and will be governed by the final adjudication of such issue.

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SIGNATURES

Pursuant to the requirements of the Securities Act of 1933, as amended, the registrant certifies that it has reasonable grounds to believe that it meets all of the requirements for filing on Form S-3 and has duly caused this registration statement to be signed on its behalf by the undersigned, thereunto duly authorized, in Oklahoma City, Oklahoma on the 18th day of April, 2017.

GULFPORT ENERGY CORPORATION

POWER OF ATTORNEY

Each person whose signature appears below hereby constitutes and appoints Michael G. Moore and Keri Crowell, and each of them, his true and lawful agent, proxy and attorney-in-fact, with full power of substitution and resubstitution, for him and in his name, place and stead, in any and all capacities, to (i) act on, sign and file with the Securities and Exchange Commission any and all amendments (including post-effective amendments) to this registration statement together with all schedules and exhibits thereto and any subsequent registration statement filed pursuant to Rule 462(b) under the Securities Act of 1933, as amended, together with all schedules and exhibits thereto, (ii) act on, sign and file such certificates, instruments, agreements and other documents as may be necessary or appropriate in connection therewith, (iii) act on and file any supplement to any prospectus included in this registration statement or any such amendment or any subsequent registration statement filed pursuant to Rule 462(b) under the Securities Act of 1933, as amended and (iv) take any and all actions which may be necessary or appropriate to be done, as fully for all intents and purposes as he might or could do in person, hereby approving, ratifying and confirming all that such agent, proxy and attorney-in-fact or any of his substitutes may lawfully do or cause to be done by virtue thereof.

Pursuant to the requirements of the Securities Act of 1933, as amended, this registration statement has been signed by the following persons in the capacities indicated on April 18, 2017.

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Gulfport Energy Corporation

Exhibit Index

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