EX-4.3


 Exhibit 4.3 

REGISTRATION RIGHTS AGREEMENT 

This Registration Rights Agreement (this “Agreement”) is made and entered into as of March 3, 2017, by and among
Gastar Exploration Inc., a Delaware corporation (the “Company”) and each of the purchasers listed on Schedule I hereto (the “Holders”). 

WHEREAS, the Holders have, pursuant to that certain Securities Purchase Agreement, dated as of February 16, 2017, by and among the
Company and the Holders (the “Purchase Agreement”), agreed to purchase (a) the Company’s Convertible Notes due 2022 (the “Notes”), which Notes are convertible into cash, newly issued shares
(the “Conversion Shares”) of common stock, par value $0.001 per share, of the Company (the “Common Stock”), or a combination of cash and Conversion Shares and (b) 29,408,305 shares (the
“Firm Shares”) of the Common Stock, subject to the terms and conditions set forth therein; and 
 WHEREAS, it is a
condition to the closing (the “Closing”) of the transactions contemplated by the Purchase Agreement that the Company and the Holders enter into this Agreement at or prior to the Closing in order to grant the Holders certain
registration rights as set forth herein. 
 NOW, THEREFORE, IN CONSIDERATION of the mutual covenants contained in this Agreement, and for
other good and valuable consideration, the receipt and adequacy of which are hereby acknowledged, the Company and the Holders agree as follows: 

1.    Definitions. Capitalized terms used and not otherwise defined herein that are defined in the
Purchase Agreement shall have the meanings given such terms in the Purchase Agreement. As used in this Agreement, the following terms shall have the respective meanings set forth in this Section 1: 

“Affiliate” of any Person shall mean any other Person directly or indirectly controlling or controlled by or under
direct or indirect common control with such Person. For purposes of this definition, “control” when used with respect to any Person has the meaning specified in Rule 12b-2 under the Exchange Act; and
the terms “controlling” and “controlled” have meanings correlative to the foregoing. 
 “Automatic Shelf
Registration Statement” means an “automatic shelf registration statement” as defined under Rule 405. 

“Available” means, with respect to a Registration Statement, that such Registration Statement does not contain an
untrue statement of a material fact or omit to state a material fact required to be stated therein or necessary to make the statements therein, in light of the circumstances under which they were made, not misleading, such that such Registration
Statement will be available for the resale of Registrable Securities. 
 “Black-Out
Period” has the meaning set forth in Section 2(b). 
 “Business Day” means a day that is a Monday,
Tuesday, Wednesday, Thursday or Friday and is not a day on which banking institutions in New York, New York generally are authorized or obligated by law, regulation or executive order to close. 






 “Commission” means the Securities and Exchange Commission or any other
federal agency then administering the Securities Act or Exchange Act. 
 “Effectiveness Date” means: 

(a)    with respect to the initial Registration Statement required to be filed to cover the resale by the
Holders of the Registrable Securities, (i) the date such Registration Statement is filed, if the Company is a WKSI as of such date, or (ii) if the Company is not a WKSI as of the date such Registration Statement is filed, the date that is
four (4) calendar months following the earlier of March 16, 2017 and the date the Company first files with the Commission its Annual Report on Form 10-K for the year ended December 31, 2016 (or
if such date is not a Business Day, the next Business Day); and 
 (b)    with respect to any additional
Registration Statements that may be required pursuant to Section 2(a) hereof, (i) if the Company is a WKSI, the date such additional Registration Statement is filed or (ii) if the Company is not a WKSI, the earlier of: (x) the 90th day following the date on which the Company first knows, or reasonably should have known, that such additional Registration Statement is required under such Section and (y) the fifth Trading
Day following the date on which the Company is notified by the Commission that such additional Registration Statement will not be reviewed or is no longer subject to further review and comments. 

“Effectiveness Period” has the meaning set forth in Section 2(a). 

“Electing Holders” means one or more Holders that hold no less than a majority of the Registrable Securities then held
by the Holders. 
 “Exchange Act” means the Securities Exchange Act of 1934, as amended. 

“Filing Date” means: 

(a)    with respect to the initial Registration Statement required to be filed to cover the resale by the
Holders of the Registrable Securities, the date that is four (4) calendar months following the Closing (or if such date is not a Business Day, the next Business Day); and 

(b)    with respect to any additional Registration Statements that may be required pursuant to Section 2(a)
hereof, the 20th Business Day following the date on which the Company first knows, or reasonably should have known, that such additional Registration Statement is required under such Section. 

“Freely Tradable” means, with respect to any security, a security that is eligible to be sold by the Holder thereof
without any volume or manner of sale restrictions under the Securities Act pursuant to Rule 144. 
 “Indemnified
Party” has the meaning set forth in Section 5(c). 

  
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 “Indemnifying Party” has the meaning set forth in Section 5(c). 

“Indenture” has the meaning set forth in the Purchase Agreement. 

“Losses” has the meaning set forth in Section 5(a). 

“Person” means an individual or corporation, partnership, trust, incorporated or unincorporated association, joint
venture, limited liability company, joint stock company, government (or an agency or subdivision thereof) or other entity of any kind. 

“Plan of Distribution” means the plan of distribution in substantially the form attached hereto as Annex A.

 “Proceeding” means a pending action, claim, suit, or proceeding (including, without limitation, an investigation
or partial proceeding, such as a deposition) or investigation known to the Company to be threatened. 
 “Prospectus”
means the prospectus included in a Registration Statement (including, without limitation, a prospectus that includes any information previously omitted from a prospectus filed as part of an effective registration statement in reliance upon Rule 430A
promulgated under the Securities Act), as amended or supplemented by any prospectus supplement, with respect to the terms of the offering of any portion of the Registrable Securities covered by a Registration Statement, and all other amendments and
supplements to the Prospectus, including post-effective amendments, and all material incorporated by reference or deemed to be incorporated by reference in such Prospectus. 

“Questionnaire” has the meaning set forth in Section 3(k). 

“Registrable Securities” means (i) the Conversion Shares issuable or issued upon conversion of the Notes,
(ii) the Firm Shares and (iii) any securities issued as (or issuable upon the conversion, exercise or exchange of any warrant, right or other security that is issued as) a dividend, stock split, combination, or any reclassification,
recapitalization, merger, consolidation, exchange or any other distribution or reorganization with respect to, or in exchange for, or in replacement of, the securities referenced in clause (i) or (ii) (without giving effect to any election by
the Company therein), above or this clause (iii); provided, however, that the term “Registrable Securities” shall exclude in all cases any securities (1) sold or exchanged by a Person pursuant to an
effective registration statement under the Act or in compliance with Rule 144, (2) that are Freely Tradable (it being understood that for purposes of determining eligibility for resale under clause (2) of this proviso, no securities held by any
Holder shall be considered Freely Tradable (x) to the extent such Holder reasonably determines that it is an Affiliate of the Company or (y) whenever a Holder, collectively with its Affiliates, owns at least (i) 25,000,000 shares of Common
Stock or (ii) $50,000,000 in recent trading value of Common Stock (including for this purpose all Conversion Shares issuable under the Notes assuming such Notes were converted entirely into Common Stock, but excluding additional “make
whole” shares unless such Holder is presently entitled to such shares) or (3) that shall have ceased to be outstanding. 

  
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 “Registration Statement” means a registration statement in the form
required to register the resale of the Registrable Securities, and including the Prospectus, amendments and supplements to each such registration statement or Prospectus, including pre- and post-effective
amendments, all exhibits thereto, and all material incorporated by reference or deemed to be incorporated by reference in such registration statement. 

“Rule 144” means Rule 144 promulgated by the Commission pursuant to the Securities Act, as such Rule may be amended
from time to time, or any similar rule or regulation hereafter adopted by the Commission having substantially the same effect as such Rule. 

“Rule 405” means Rule 405 promulgated by the Commission pursuant to the Securities Act, as such Rule may be amended
from time to time, or any similar rule or regulation hereafter adopted by the Commission having substantially the same effect as such Rule. 

“Rule 415” means Rule 415 promulgated by the Commission pursuant to the Securities Act, as such Rule may be amended
from time to time, or any similar rule or regulation hereafter adopted by the Commission having substantially the same effect as such Rule. 

“Rule 424” means Rule 424 promulgated by the Commission pursuant to the Securities Act, as such Rule may be amended
from time to time, or any similar rule or regulation hereafter adopted by the Commission having substantially the same effect as such Rule. 

“Rule 433” means Rule 433 promulgated by the Commission pursuant to the Securities Act, as such Rule may be amended
from time to time, or any similar rule or regulation hereafter adopted by the Commission having substantially the same effect as such Rule. 

“Securities Act” means the Securities Act of 1933, as amended. 

“Suspension Notice” has the meaning set forth in Section 3(j)(B). 

“S-1 Amendment Period” has the meaning set forth in Section 2(a). 

“Trading Day” means a day during which trading in the Common Stock generally occurs. 

“Trading Market” means the principal national securities exchange on which the Common Stock is listed. 

“Use Notice” has the meaning set forth in Section 3(j). 

“WKSI” means a “well known seasoned issuer” as defined under Rule 405. 

2.    Registration. 

(a)    On or prior to each Filing Date, the Company will use reasonable best efforts to prepare and file with the
Commission a Registration Statement covering the resale of all Registrable Securities not already covered by an existing and effective Registration Statement for an offering to be made on a continuous basis pursuant to Rule 415. The Registration
Statement (i) shall be on Form S-3 (except if the Company is not then eligible to register for 

  
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resale the Registrable Securities on Form S-3, in which case such registration shall be on another appropriate form for such purpose, including Form S-1) and, if the Company is a WKSI as of the Filing Date, shall be an Automatic Shelf Registration Statement and (ii) shall contain (except if otherwise requested by the Electing Holders or required pursuant to
written comments received from the Commission upon a review of such Registration Statement) the Plan of Distribution. The Company will use its reasonable best efforts to cause the Registration Statement to be declared effective or otherwise to
become effective under the Securities Act as soon as possible but, in any event, no later than the Effectiveness Date, and will use its reasonable best efforts to keep the Registration Statement (or a replacement Registration Statement) continuously
effective under the Securities Act until the registration rights under this Agreement terminate in accordance with Section 2(c) (the “Effectiveness Period”). In addition, the Company will, promptly and from time to time, use
reasonable best efforts to file such additional Registration Statements to cover resales of any Registrable Securities which are not registered for resale pursuant to a pre-existing Registration Statement no
later than the Filing Date with respect thereto, and will use its reasonable best efforts to cause such Registration Statement to be declared effective or otherwise to become effective under the Securities Act as soon as practicable after the
applicable Filing Date but, in any event, no later than the applicable Effectiveness Date, and will use its reasonable best efforts to keep the Registration Statement continuously effective under the Securities Act at all times during the
Effectiveness Period; provided that, the Company will not be obligated to update the Registration Statement and no sales may made under the applicable Registration Statement during any Black-Out Period
of which the Holders have received actual notice; and provided further, that if the Registration Statement is on Form S-1, the Effectiveness Period shall not include (and the Company shall not be
required to keep the Registration Statement effective during) any period commencing on the date an amendment to the Registration Statement is required to be filed, or has been filed and the amended Registration Statement not yet declared effective
by the Commission, to update information as a result of the filing by the Company of an Annual Report on Form 10-K or any other material development that would require, in the reasonable judgment of legal
counsel to the Company or upon advice from the staff of the Commission, an amendment to such Registration Statement, provided (i) any required amendment to the Registration Statement is filed promptly by the Company, (ii) any comments of
the staff of the Commission with respect to such amended Registration Statement are addressed promptly by the Company and (iii) a request for declaration of effectiveness of such amended Registration Statement is requested by the Company for a
date which is not more than five (5) Trading Days following the date of receipt of notice or other communication from the staff of the Commission that it has no further comments to the amended Registration Statement (such period, until such
amended Registration Statement is declared effective by the Commission, being herein referred to as an “S-1 Amendment Period”). 

(b)    If the Company at any time during a period the Registration Statement is effective reasonably determines in good
faith and in its reasonable judgment, and based on the advice of outside legal counsel, that (i) the ongoing registration would be reasonably likely to materially interfere with a bona fide business or financing transaction of the Company,
would require premature disclosure of information (the premature disclosure of which could materially and adversely affect the Company) or would otherwise be seriously detrimental to the Company or (ii) that the Registration Statement is
subject to a stop order, is no longer effective or is otherwise not Available for use, the Company may suspend sales of securities pursuant to the 

  
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Registration Statement for a period of not more than seventy five (75) consecutive calendar days or an aggregate of one hundred twenty (120) days in any twelve month period (a
“Black-Out Period”) and agrees to (i) furnish to each Holder a certificate signed by an officer of the Company to that effect and (ii) notify each Holder promptly upon each of
the commencement and termination of each Black-Out Period. Each Holder agrees that, upon any such notice from the Company, it will forthwith discontinue disposition of Registrable Securities pursuant to the
Registration Statement until receipt of the Company’s notice as to the termination of the Black-Out Period. Each of the Holders agree to keep the notice of
Black-Out Period confidential and shall not disclose such notice or reasons to any Person other than such Holder’s legal counsel or as required by law. For the avoidance of doubt, an S-1 Amendment Period shall not be considered a Black-Out Period. 

(c)    The registration rights granted under this Section 2 shall automatically terminate at such time as there
are no outstanding Registrable Securities. 
 3.    Registration Procedures. 

The procedures to be followed by the Company and each selling Holder, and the respective rights and obligations of the Company and such
Holders, with respect to the preparation, filing and effectiveness of a Registration Statement, and the distribution of Registrable Securities pursuant thereto, are as follows: 

(a)    The Company will, at least five (5) Trading Days prior to the filing of a Registration Statement or any
related Prospectus or any amendment or supplement thereto (other than any amendment or supplement made through the incorporation by reference of, or if the Registration Statement is on Form S-1 made solely for
the purpose of including, ordinary course Exchange Act filings), (i) furnish to the Holders copies of all such documents proposed to be filed, which documents will be subject to the reasonable review of such Holders and (ii) use its reasonable
best efforts to address in each such document when so filed with the Commission such comments as the Holders reasonably shall propose. 

(b)    Subject to Section 2, the Company will use reasonable best efforts to (i) prepare and file with the
Commission such amendments, including post-effective amendments, and supplements to each Registration Statement and the Prospectus used in connection therewith as may be necessary under applicable law with respect to the disposition of all
Registrable Securities covered by such Registration Statement and prepare and file with the Commission such additional Registration Statements in order to register for resale under the Securities Act all of the Registrable Securities;
(ii) cause the related Prospectus to be amended or supplemented by any required Prospectus supplement, and as so supplemented or amended to be filed pursuant to Rule 424; and (iii) respond as promptly as reasonably possible to any comments
received from the Commission with respect to each Registration Statement or any amendment thereto and, as promptly as reasonably possible provide the Holders true and complete copies of all correspondence from and to the Commission relating to such
Registration Statement that pertains to the Holders as selling securityholders but not any comments that would result in the disclosure to the Holders of material and non-public information concerning the
Company. 

  
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 (c)    The Company will comply in all material respects with the provisions
of the Securities Act and the Exchange Act with respect to the Registration Statements and the disposition of all Registrable Securities covered by each Registration Statement. 

(d)    The Company will notify the Holders as promptly as reasonably possible of (i) the issuance by the Commission
of any stop order suspending the effectiveness of a Registration Statement covering any or all of the Registrable Securities or the initiation of any Proceedings for that purpose; and (ii) the receipt by the Company of any notification with
respect to the suspension of the qualification or exemption from qualification of any of the Registrable Securities for sale in any jurisdiction, or the initiation or threatening of any Proceeding for such purpose. 

(e)    The Company will use reasonable best efforts to obtain the withdrawal of any order suspending the effectiveness of
a Registration Statement, at the earliest practicable moment, or if any such order or suspension is made effective during any Black-Out Period, at the earliest practicable moment after the Black-Out Period is over. 
 (f)    During the Effectiveness Period, the Company will
furnish to each Holder, without charge, at least one conformed copy of each Registration Statement and each amendment thereto and all exhibits to the extent requested by such Person (including those incorporated by reference) promptly after the
filing of such documents with the Commission; provided, that the Company will not have any obligation to provide any document pursuant to this clause that is available on the EDGAR system. 

(g)    The Company will promptly deliver to each Holder, without charge, as many copies of each Prospectus or Prospectuses
(other than any amendment or supplement made through the incorporation by reference of ordinary course Exchange Act filings) as such Persons may reasonably request during the Effectiveness Period. The Company consents to the use of such Prospectus
and each amendment or supplement thereto by each of the selling Holders in connection with the offering and sale of the Registrable Securities covered by such Prospectus and any amendment or supplement thereto in accordance with this Agreement. 

(h)    The Company will, prior to any public offering of Registrable Securities, use reasonable best efforts to register
or qualify or cooperate with the selling Holders in connection with the registration or qualification (or exemption from such registration or qualification) of such Registrable Securities for offer and sale under the applicable state securities or
blue sky laws of those jurisdictions within the United States as any Holder reasonably requests in writing to keep each such registration or qualification (or exemption therefrom) effective during the Effectiveness Period and use its reasonable best
efforts to do any and all other acts or things necessary or advisable to enable the disposition in such jurisdictions of the Registrable Securities covered by the Registration Statements; provided, that the Company will not be required to
(i) qualify generally to do business or as a dealer in securities in any jurisdiction where it is not then so qualified or (ii) take any action which would subject the Company to general service of process or any material tax in any such
jurisdiction where it is not then so subject. 

  
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 (i)    The Company will cooperate with the Holders to facilitate the timely
preparation and delivery of certificates representing Registrable Securities to be delivered to a transferee pursuant to a sale or proposed sale effected pursuant to the Registration Statements, which certificates shall be free, of all restrictive
legends, and to enable such Registrable Securities to be in such denominations and registered in such names as any such Holders may request in writing. In connection therewith, if required by the Company’s transfer agent, the Company will
promptly after the effectiveness of the Registration Statement cause an opinion of counsel as to the effectiveness of the Registration Statement to be delivered to its transfer agent when and as required by such transfer agent from time to time,
together with any other authorizations, certificates and directions required by the transfer agent which authorize and direct the transfer agent to issue such Registrable Securities without legend upon sale by the holder of such shares of
Registrable Securities under the Registration Statement. 
 (j)    Subject to Section 2, the Company will use
reasonable best efforts to prepare such supplements or amendments, including a post-effective amendment, if required by applicable law, to each applicable Registration Statement and file any other required document so that such Registration
Statement will be Available at all times during the Effectiveness Period; provided, that no such supplement, amendment or filing will be required during a Black-Out Period. No later than 8:00 p.m. (New
York time) on any Trading Day on which the Company receives a written notice (a “Use Notice”) prior to 2:00 p.m. (New York time) on such Trading Day (or if such request is received after 2:00 p.m. (New York time), no later
than 8:00 p.m. (New York time) on the following Trading Day) from a Holder that such Holder intends to use the Registration Statement to resell Registrable Securities, the Company will (A) provide written confirmation to such Holder that the
applicable Registration Statement is Available or (B) provide written notice (a “Suspension Notice”) that the use of such Registration Statement is suspended due to a Black-Out
Period. No Suspension Notice will contain the reason for the Black-Out Period. The Company will promptly provide the Holders written notice when the Black-Out Period
ends. If a Black-Out Period commences during any 30 Trading Day period following delivery of a Use Notice and a notice from the Company under clause (A) above, the Company will provide as promptly as
practicable the Holders with written notice thereof and that the Registration Statement is no longer Available. 

(k)    Notwithstanding any other provision of the Agreement, no Holder of Registrable Securities may include any of its
Registrable Securities in the Registration Statement pursuant to this Agreement unless the Holder furnishes to the Company a completed questionnaire substantially in the form of Exhibit A (the “Questionnaire”) for use in
connection with the Registration Statement at least five (5) Trading Days prior to the filing of the Registration Statement or an amendment thereof; provided, however, that unless reasonably requested by the Company in writing, a
Holder shall not be required to furnish a Questionnaire in connection with the initial Registration Statement if such Holder owns Notes or Firm Shares initially purchased by such Holder at the Closing as of the initial Filing Date. Each Holder who
intends to include any of its Registrable Securities in the Registration Statement shall promptly furnish the Company in writing such other information as the Company may reasonably request in writing. 

(l)    The Holders may distribute the Registrable Securities by means of up to four underwritten offerings;
provided that (a) the Electing Holders provide written notice to the 

  
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Company of their intention to distribute Registrable Securities by means of an underwritten offering, (b) the managing underwriter or underwriters thereof shall be designated by the Electing
Holders, provided, however, that such designated managing underwriter or underwriters shall be reasonably acceptable to the Company, (c) each Holder participating in such underwritten offering agrees to sell such Holder’s
Registrable Securities on the basis provided in any underwriting arrangements approved by the persons entitled selecting the managing underwriter or underwriters hereunder and (d) each Holder participating in such underwritten offering
completes and executes all questionnaires, powers of attorney, indemnities, underwriting agreements and other documents reasonably required under the terms of such underwriting arrangements. The Company hereby agrees with each Holder that, in
connection with any underwritten offering in accordance with the terms hereof, it will negotiate in good faith and execute all indemnities, underwriting agreements and other documents reasonably required under the terms of such underwriting
arrangements, including using reasonable best efforts to procure customary legal opinions and auditor “cold comfort” letters. 

(m)    In the event the Holders seek to complete an underwritten offering pursuant to Section 3(l), for a reasonable
period prior to the filing of any Registration Statement, and throughout the Effectiveness Period, the Company will make available upon reasonable notice at the Company’s principal place of business or such other reasonable place for inspection
by the managing underwriter or underwriters selected in accordance with Section 3(l), such financial and other information and books and records of the Company, and cause the officers, employees, counsel and independent certified public accountants
of the Company to respond to such inquiries, as shall be reasonably necessary (and in the case of counsel, not violate an attorney-client privilege in such counsel’s reasonable belief), to conduct a reasonable investigation within the meaning
of Section 11 of the Securities Act; provided, however, that the foregoing inspection and information gathering on behalf of the Holders (and any managing underwriter or underwriters) shall be conducted by legal counsel to the
Holders (and legal counsel to such managing underwriter or underwriters); provided further, that each such party shall be required to maintain in confidence and not to disclose to any other Person any information or records reasonably
designated by the Company as being confidential, until such time as (A) such information becomes a matter of public record (whether by virtue of its inclusion in the Registration Statement or in any other manner other than through the release
of such information by any Person afforded access to such information pursuant hereto), or (B) such Person shall be required so to disclose such information pursuant to a subpoena or order of any court or other governmental agency or body
having jurisdiction over the matter (subject to the requirements of such order, and only after such Person shall have given the Company prompt prior written notice of such requirement). 

4.    Registration Expenses. All fees and expenses incident to the Company’s performance of or
compliance with their obligations under this Agreement (excluding any underwriting discounts and selling commissions, but including legal fees and expenses of one legal counsel to the Holders of up to $50,000 in connection with the initial filing
and for each underwritten offering) shall be borne by the Company whether or not any Registrable Securities are sold pursuant to a Registration Statement. The fees and expenses referred to in the foregoing sentence shall include, without limitation,
(i) all registration and filing fees (including, without limitation, fees and expenses (A) with respect to filings required to be made with the Trading Market, and (B) in compliance with applicable state securities or blue sky laws),
(ii) printing 

  
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expenses (including, without limitation, expenses of printing certificates for Registrable Securities and of printing prospectuses if the printing of prospectuses is reasonably requested by the
Electing Holders included in the Registration Statement), (iii) messenger, telephone and delivery expenses, (iv) fees and disbursements of counsel for the Company, (v) Securities Act liability insurance, if the Company so desires such
insurance, and (vi) fees and expenses of all other Persons retained by the Company in connection with the consummation of the transactions contemplated by this Agreement. In addition, the Company shall be responsible for all of their internal
expenses incurred in connection with the consummation of the transactions contemplated by this Agreement (including, without limitation, all salaries and expenses of their officers and employees performing legal or accounting duties), the expense of
any annual audit and the fees and expenses incurred in connection with the listing of the Registrable Securities on any securities exchange as required hereunder. For the avoidance of doubt, each Holder shall pay all underwriting and placement
discounts and commissions, agency and placement fees, brokers’ commissions and transfer taxes, if any, relating to the sale or disposition of such Holder’s Registrable Securities. 

5.    Indemnification. 

(a)    Indemnification by the Company. The Company will, notwithstanding any termination of this Agreement, jointly
and severally, indemnify and hold harmless each Holder and each underwriter, broker-dealer or selling agent, if any, which facilitates the disposition of Registrable Securities, the officers, directors, agents, partners, members, stockholders and
employees of each of them, each Person who controls any such Holder, underwriter, broker-dealer or selling agent (within the meaning of Section 15 of the Securities Act or Section 20 of the Exchange Act) and the officers, directors, agents
and employees of each such controlling Person, to the fullest extent permitted by applicable law, from and against any and all losses, claims, damages, liabilities, costs (including, without limitation, reasonable costs of preparation and reasonable
attorneys’ fees) and expenses (collectively, “Losses”), as incurred, arising out of or relating to any untrue or alleged untrue statement of a material fact contained in any Registration Statement, any Prospectus or any
form of prospectus (including, without limitation, any “issuer free writing prospectus” as defined in Rule 433), or any “road show” (as defined in Rule 433 of the rules and regulations of the Commission under the Securities Act)
that does not otherwise constitute an “issuer free writing prospectus,” or in any amendment or supplement thereto or in any preliminary prospectus, or arising out of or relating to any omission or alleged omission of a material fact
required to be stated therein or necessary to make the statements therein (in the case of any Prospectus or form of prospectus (including, without limitation, any “issuer free writing prospectus” as defined in Rule 433) or supplement
thereto, in light of the circumstances under which they were made) not misleading, except to the extent, but only to the extent, that (i) such Losses arise out of or are based upon any untrue statements, alleged untrue statements, omissions or
alleged omissions that are based solely upon information regarding such Holder, underwriter, broker-dealer or selling agent furnished in writing to the Company by such Person expressly for use therein in the Questionnaire or pursuant to Section 3(k)
or (ii) such Losses arise out of or are based upon transfers of Registrable Securities during a Black-Out Period of which the Holders received actual notice. The Company shall notify the Holders promptly
of the institution, threat or assertion of any Proceeding of which the Company is aware in connection with the transactions contemplated by this Agreement. 

  
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 (b)    Indemnification by Holders. Each Holder shall, notwithstanding
any termination of this Agreement, severally and not jointly, indemnify and hold harmless the Company, its directors, officers, agents and employees, each Person who controls the Company (within the meaning of Section 15 of the Securities Act
and Section 20 of the Exchange Act), and the directors, officers, agents or employees of such controlling Persons, to the fullest extent permitted by applicable law, from and against all Losses, as incurred, arising solely out of or based
solely upon any untrue statement of a material fact contained in any Registration Statement, any Prospectus, or any form of prospectus (including, without limitation, any “issuer free writing prospectus” as defined in Rule 433), or in any
amendment or supplement thereto, or arising solely out of or based solely upon any omission of a material fact required to be stated therein or necessary to make the statements therein (in the case of any Prospectus, or any form of prospectus
(including, without limitation, any “issuer free writing prospectus” as defined in Rule 433) or supplement thereto, in light of the circumstances under which they were made) not misleading to the extent, but only to the extent, that such
untrue statements or omissions are based solely upon information regarding such Holder furnished in writing to the Company by such Holder in the Questionnaire or pursuant thereto. In no event shall the liability of any selling Holder hereunder be
greater in amount than the dollar amount of the net proceeds received by such Holder upon the sale of the Registrable Securities giving rise to such indemnification obligation. 

(c)    Conduct of Indemnification Proceedings. If any Proceeding shall be brought or asserted against any Person
entitled to indemnity hereunder (an “Indemnified Party”), such Indemnified Party shall promptly notify the Person from whom indemnity is sought (the “Indemnifying Party”) in writing, and the
Indemnifying Party shall be permitted to assume the defense thereof, including the employment of counsel reasonably satisfactory to the Indemnified Party (whose approval shall not be unreasonably withheld) and the payment of all fees and expenses
incurred in connection with defense thereof; provided, that the failure of any Indemnified Party to give such notice shall not relieve the Indemnifying Party of its obligations or liabilities pursuant to this Agreement, except (and only) to
the extent that it shall be finally determined by a court of competent jurisdiction (which determination is not subject to appeal or further review) that such failure shall have proximately and materially adversely prejudiced the Indemnifying Party.

 An Indemnified Party shall have the right to employ separate counsel in any such Proceeding and to participate in the defense thereof,
but the fees and expenses of such counsel shall be at the expense of such Indemnified Party or Parties unless: (1) the Indemnifying Party has agreed in writing to pay such fees and expenses; (2) the Indemnifying Party shall have failed
promptly to assume the defense of such Proceeding and to employ counsel reasonably satisfactory to such Indemnified Party in any such Proceeding (whose approval shall not be unreasonably withheld); or (3) the named parties to any such
Proceeding (including any impleaded parties) include both such Indemnified Party and the Indemnifying Party, and such Indemnified Party shall have been advised by counsel that a conflict of interest is likely to exist if the same counsel were to
represent such Indemnified Party and the Indemnifying Party (in which case, if such Indemnified Party notifies the Indemnifying Party in writing that it elects to employ separate counsel at the expense of the Indemnifying Party, the Indemnifying
Party shall not have the right to assume the defense thereof and such counsel shall be at the expense of the Indemnifying Party); provided that the Indemnifying Party shall not be liable for the fees and


  
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expenses of more than one separate firm of attorneys at any time for all Indemnified Parties. The Indemnifying Party shall not be liable for any settlement of any such Proceeding effected
without its written consent, which consent shall not be unreasonably withheld. No Indemnifying Party shall, without the prior written consent of the Indemnified Party, effect any settlement of any pending Proceeding in respect of which any
Indemnified Party is a party, unless such settlement includes an unconditional release of such Indemnified Party from all liability on claims that are the subject matter of such Proceeding and does not include a statement as to or any admission of
fault, culpability or failure to act by any Indemnified Party. 
 All fees and expenses of the Indemnified Party (including reasonable fees
and expenses to the extent incurred in connection with investigating or preparing to defend such Proceeding in a manner not inconsistent with this Section) shall be paid to the Indemnified Party, as incurred, promptly upon receipt of written notice
thereof to the Indemnifying Party (regardless of whether it is ultimately determined that an Indemnified Party is not entitled to indemnification hereunder; provided that the Indemnifying Party may require such Indemnified Party to undertake
to reimburse all such fees and expenses to the extent it is finally judicially determined that such Indemnified Party is not entitled to indemnification hereunder). 

(d)    Contribution. If a claim for indemnification under Section 5(a) or 5(b) is unavailable to an Indemnified
Party (by reason of public policy or otherwise), then each Indemnifying Party, in lieu of indemnifying such Indemnified Party, shall contribute to the amount paid or payable by such Indemnified Party as a result of such Losses, in such proportion as
is appropriate to reflect the relative fault of the Indemnifying Party and Indemnified Party in connection with the actions, statements or omissions that resulted in such Losses as well as any other relevant equitable considerations. The
relative fault of such Indemnifying Party and Indemnified Party shall be determined by reference to, among other things, whether any action in question, including any untrue or alleged untrue statement of a material fact or omission or alleged
omission of a material fact, has been taken or made by, or relates to information supplied by, such Indemnifying Party or Indemnified Party, and the parties’ relative intent, knowledge, access to information and opportunity to correct or
prevent such action, statement or omission. The amount paid or payable by a party as a result of any Losses shall be deemed to include, subject to the limitations set forth in Section 5(c), any reasonable attorneys’ or other reasonable
fees or expenses incurred by such party in connection with any Proceeding to the extent such party would have been indemnified for such fees or expenses if the indemnification provided for in this Section was available to such party in accordance
with its terms. 
 The parties hereto agree that it would not be just and equitable if contribution pursuant to this Section 5(d) were
determined by pro rata allocation or by any other method of allocation that does not take into account the equitable considerations referred to in the immediately preceding paragraph. Notwithstanding the provisions of this Section 5(d), no
Holder shall be required to contribute, in the aggregate, any amount in excess of the amount by which the proceeds actually received by such Holder, net of any stock transfer taxes or underwriting or brokers’ commissions paid by such Holder,
from the sale of the Registrable Securities subject to the Proceeding exceeds the amount of any damages, indemnity or contribution that such Holder has otherwise been required to pay by reason of such untrue or alleged untrue statement or omission
or alleged omission. No Person guilty of fraudulent misrepresentation (within the meaning of Section 11(f) of the Securities Act) shall be entitled to contribution from any Person who was not guilty of such fraudulent misrepresentation. 

  
 12 







 The indemnity and contribution agreements contained in this Section are in addition to any
liability that the Indemnifying Parties may have to the Indemnified Parties and are not in diminution or limitation of the indemnification provisions under the Purchase Agreement. 

6.    Facilitation of Sales Pursuant to Rule 144. To the extent it shall be required to do so under
the Exchange Act, the Company shall timely file the reports required to be filed by it under the Exchange Act or the Securities Act (including the reports under Sections 13 and 15(d) of the Exchange Act referred to in subparagraph (c)(1) of
Rule 144) and submit all required Interactive Data Files (as defined in Rule 11 of Regulation S-T of the Commission), and shall take such further action as any Holder may reasonably request, all to the
extent required from time to time to enable the Holders to sell Registrable Securities without registration under the Securities Act within the limitations of the exemption provided by Rule 144. Upon the request of any Holder in connection with
that Holder’s sale pursuant to Rule 144, the Company shall deliver to such Holder a written statement as to whether it has complied with such requirements. 

7.    Miscellaneous. 

(a)    Remedies. In the event of a breach by the Company or by a Holder, of any of their obligations under this
Agreement, each Holder or the Company, as the case may be, in addition to being entitled to exercise all rights granted by law and under this Agreement, including recovery of damages, will be entitled to specific performance of its rights under this
Agreement. The Company and each Holder agree that monetary damages alone would not provide adequate compensation for any Losses incurred by reason of a breach by it of any of the provisions of this Agreement and further agree that, in the event
of any action for specific performance in respect of such breach, it shall waive the defense that a remedy at law would be adequate. 

(b)    Discontinued Disposition. Each Holder agrees by its acquisition of such Registrable Securities that, that it
will not commence a disposition of Registrable Securities under the Registration Statement until such Holder has received (A) written confirmation from the Company of the availability of the Registration Statement as described in Section
3(j)(A), (B) written confirmation from the Company that the Black-Out Period has ceased as described in Section 3(j) or (C) copies of the supplemented Prospectus and/or amended Registration Statement as
described in Section 3(j), and, in each case, has also received copies of any additional or supplemental filings that are incorporated or deemed to be incorporated by reference in such Prospectus or Registration Statement. The Company may
provide appropriate stop orders to enforce the provisions of this paragraph. 
 (c)    Amendments and Waivers. No
provision of this Agreement may be waived or amended except in a written instrument signed by the Company and the Electing Holders. No waiver of any default with respect to any provision, condition or requirement of this Agreement shall be deemed to
be a continuing waiver in the future or a waiver of any subsequent default or a waiver of any other provision, condition or requirement hereof, nor shall any delay or omission of either party to exercise any right hereunder in any manner impair the
exercise of any such right. 

  
 13 







 (d)    Notices. Except where explicitly stated otherwise, any and all
notices or other communications or deliveries required or permitted to be provided hereunder shall be in writing (which shall include emails to each of the email addresses specified for such party below) and shall be deemed given and effective on
the earliest of (i) the date of transmission, if such notice or communication is delivered via facsimile or email as specified in this Section prior to 5:00 p.m. (New York time) on a Business Day, (ii) the Business Day after the date of
transmission, if such notice or communication is delivered via facsimile or electronic mail as specified in this Agreement later than 5:00 p.m. (New York time) on any date and earlier than 11:59 p.m. (New York time) on such date, (iii) the
Business Day following the date of mailing, if sent by nationally recognized overnight courier service, or (iv) upon actual receipt by the party to whom such notice is required to be given. The address for such notices and communications
shall be as follows: 
 (i)    If to the Company, addressed as follows: 

Gastar Exploration Inc. 
 1331
Lamar Street, Suite 650 
 Houston, TX 77010 

Facsimile No.: 713-729-0458 

Attention: J. Russell Porter, President and CEO 

                 Michael A. Gerlich, SVP and Chief
Financial Officer 
 E-mail:     rporter@gastar.com 

                 mgerlich@gastar.com 

with a copy (which shall not constitute notice) to: 

Vinson & Elkins LLP 

1001 Fannin Street, Suite 2500 

Houston, TX 77002 
 Facsimile
No.: 713-615-5962 
 Attention: David H. Stone and James M.
Prince 
 Email:      dstone@velaw.com 

                 jprince@velaw.com 

  
 14 







 (ii)    If to any Holder, addressed as follows: 

Ares Management LLC 
 2000
Avenue of the Stars, 12th Floor 
 Los Angeles, CA 90067 

Attention: Nate Walton, Jesse Yanocha, Preston Hayes and Eric Waxman 

Email:       walton@aresmgmt.com 

 jyanocha@aresmgmt.com 

 phayes@aresmgmt.com 

 ewaxman@aresmgmt.com 

with a copy (which shall not constitute notice) to: 

811 Main Street, Suite 3700 

Houston, TX 77002 
 Facsimile:
(713) 546-5401 
 Attention:  Michael Chambers and Greg Rodgers 

Email:        michael.chambers@lw.com 

 greg.rodgers@lw.com 
 or such other
address as may be designated in writing hereafter, in the same manner, by such Person. 
 (e)    Successors and
Assigns. This Agreement shall inure to the benefit of and be binding upon the successors and permitted assigns of each of the parties and shall inure to the benefit of each Holder; provided, however, that nothing herein shall be
deemed to permit any assignment, transfer or other disposition of Registrable Securities in violation of the terms of the Indenture. The Company may not assign (other than by operation of law) its rights or obligations hereunder without the prior
written consent of the Electing Holders. The Holders may not assign their rights and obligations hereunder (other than by operation of law); provided that a Holder may assign its rights and obligations hereunder to an Affiliate of such
Holder. 
 (f)    Execution and Counterparts. This Agreement may be executed in any number of counterparts, each
of which when so executed shall be deemed to be an original and, all of which taken together shall constitute one and the same Agreement. In the event that any signature is delivered by facsimile or electronic mail transmission, such signature
shall create a valid binding obligation of the party executing (or on whose behalf such signature is executed) the same with the same force and effect as if such signature delivered by facsimile or electronic mail transmission were the original
thereof. 
 (g)    Governing Law. This Agreement shall be governed by and construed in accordance with the laws
of the State of New York. 
 (h)    Submission to Jurisdiction. Each of the parties to this Agreement irrevocably
and unconditionally submits, for itself and its property, to the exclusive jurisdiction of the courts of the State of New York sitting in New York County and of the United States District Court of the Southern District of New York, and any appellate
court from any thereof, in any Proceeding arising out of or relating to this Agreement, or for the recognition or enforcement 

  
 15 







 
of any judgment, and each of the parties hereto irrevocably and unconditionally agrees that all claims in respect of any such Proceeding may be heard and determined in such New York State court
or, to the fullest extent permitted by applicable law, in such federal court. Each of the parties hereto agrees that a final judgment in any such Proceeding shall be conclusive and may be enforced in other jurisdictions by suit on the judgment or in
any other manner provided by law. 
 (i)    Waiver of Venue. Each of the parties to this Agreement irrevocably
and unconditionally waives, to the fullest extent permitted by applicable law, (i) any objection that it may now or hereafter have to the laying of venue of any Proceeding arising out of or relating to this Agreement in any court referred to in
Section 7(h) and (ii) the defense of an inconvenient forum to the maintenance of such Proceeding in any such court. 

(j)    Cumulative Remedies. The remedies provided herein are cumulative and not exclusive of any remedies provided
by law. 
 (k)    Severability. If any term, provision, covenant or restriction of this Agreement is held by a
court of competent jurisdiction to be invalid, illegal, void or unenforceable, the remainder of the terms, provisions, covenants and restrictions set forth herein shall remain in full force and effect and shall in no way be affected, impaired or
invalidated, and the parties hereto shall use their reasonable efforts to find and employ an alternative means to achieve the same or substantially the same result as that contemplated by such term, provision, covenant or restriction. It is
hereby stipulated and declared to be the intention of the parties that they would have executed the remaining terms, provisions, covenants and restrictions without including any of such that may be hereafter declared invalid, illegal, void or
unenforceable. 
 (l)    Entire Agreement. This Agreement constitutes the entire agreement between the parties
hereto pertaining to the subject matter hereof, and supersedes all other prior agreements and understandings, both written and oral, between the parties, with respect to the subject matter hereof. 

(m)    Headings; Section References. The headings in this Agreement are for convenience of reference only and shall
not limit or otherwise affect the meaning hereof. Unless otherwise stated, references to Sections, Schedules and Exhibits are to the Sections, Schedules and Exhibits of this Agreement. 

[Signature Pages Follow] 

  
 16 







 IN WITNESS WHEREOF, the parties have executed this Registration Rights Agreement as of the date
first written above. 
  

			
	COMPANY:
	
	GASTAR EXPLORATION INC.
		
	By:	 	 /s/ Michael A. Gerlich

	Name:	 	Michael A. Gerlich
	Title:	 	 Senior Vice President, Chief
 Financial
Officer and Corporate Secretary




  
 [Signature Page to the
Registration Rights Agreement] 







 IN WITNESS WHEREOF, the parties have executed or caused this Agreement to be executed as of the
date first written above. 
  

			
	HOLDERS:
	
	 AF V ENERGY I AIV A1, L.P.

AF V ENERGY I AIV A2, L.P.
 AF V ENERGY I AIV A3,
L.P.
 AF V ENERGY I AIV A4, L.P.
 AF V ENERGY I
AIV A5, L.P.
 AF V ENERGY I AIV A6, L.P.
 AF V
ENERGY I AIV A7, L.P.
 AF V ENERGY I AIV A8, L.P.

AF V ENERGY I AIV A9, L.P.
 AF V ENERGY I AIV A10,
L.P.
 AF V ENERGY I AIV A11, L.P.
 AF V ENERGY I
AIV A12, L.P.
 AF V ENERGY I AIV A13, L.P.













	AF V ENERGY I AIV B1, L.P.
		
	 By:
	 	AF V Energy I AIV GP, L.P.,
		 	  as general partner
		
	 By:
	 	 /s/ Jesse Yanocha

	 Name:
	 	Jesse Yanocha
	 Title:
	 	Authorized Signatory



  
 [Signature Page to the
Registration Rights Agreement] 







 SCHEDULE I 

AF V Energy I AIV A1 L.P. 
 AF V Energy I AIV A2 L.P. 

AF V Energy I AIV A3 L.P. 
 AF V Energy I AIV A4 L.P. 

AF V Energy I AIV A5 L.P. 
 AF V Energy I AIV A6 L.P. 

AF V Energy I AIV A7 L.P. 
 AF V Energy I AIV A8 L.P. 

AF V Energy I AIV A9 L.P. 
 AF V Energy I AIV A10 L.P. 

AF V Energy I AIV A11 L.P. 
 AF V Energy I AIV A12 L.P. 

AF V Energy I AIV A13 L.P. 
 AF V Energy I AIV B1 L.P. 






 ANNEX A 

PLAN OF DISTRIBUTION 
 The
selling securityholders, including their pledgees, donees, transferees, distributees, beneficiaries or other successors in interest, may from time to time offer some or all of the shares of common stock (collectively,
“Securities”) covered by this prospectus. To the extent required, this prospectus may be amended and supplemented from time to time to describe a specific plan of distribution. 

The selling securityholders will not pay any of the costs, expenses and fees in connection with the registration and sale of the shares
covered by this prospectus, but they will pay any and all underwriting discounts, selling commissions and stock transfer taxes, if any, attributable to sales of the shares. We will not receive any proceeds from the sale of the shares of common stock
covered hereby. 
 The selling securityholders may sell the Securities covered by this prospectus from time to time, and may also decide not
to sell all or any of the Securities that they are allowed to sell under this prospectus. The selling securityholders will act independently of us in making decisions regarding the timing, manner and size of each sale. These dispositions may be at
fixed prices, at market prices prevailing at the time of sale, at prices related to such prevailing market prices, at varying prices determined at the time of sale, or at privately negotiated prices. Sales may be made by the selling securityholders
in one or more types of transactions, which may include: 
  

	 	•	 	purchases by underwriters, dealers and agents who may receive compensation in the form of underwriting discounts, concessions or commissions from the selling securityholders and/or the purchasers of the Securities for
whom they may act as agent; 

  

	 	•	 	one or more block transactions, including transactions in which the broker or dealer so engaged will attempt to sell the Securities as agent but may position and resell a portion of the block as principal to facilitate
the transaction, or in crosses, in which the same broker acts as an agent on both sides of the trade; 

  

	 	•	 	ordinary brokerage transactions or transactions in which a broker solicits purchases; 

  

	 	•	 	purchases by a broker-dealer or market maker, as principal, and resale by the broker-dealer for its account; 

  

	 	•	 	the pledge of Securities for any loan or obligation, including pledges to brokers or dealers who may from time to time effect distributions of Securities; 


 

	 	•	 	short sales or transactions to cover short sales relating to the Securities; 








	 	•	 	one or more exchanges or over the counter market transactions; 

  

	 	•	 	through distribution by a selling securityholder or its successor in interest to its members, general or limited partners or shareholders (or their respective members, general or limited partners or shareholders);


  

	 	•	 	privately negotiated transactions; 

  

	 	•	 	the writing of options, whether the options are listed on an options exchange or otherwise; 

  

	 	•	 	distributions to creditors and equity holders of the selling securityholders; and 

  

	 	•	 	any combination of the foregoing, or any other available means allowable under applicable law. 


A selling securityholder may also resell all or a portion of its Securities in open market transactions in reliance upon Rule 144 under the
Securities Act provided it meets the criteria and conforms to the requirements of Rule 144. 
 The selling securityholders may enter into
sale, forward sale and derivative transactions with third parties, or may sell securities not covered by this prospectus to third parties in privately negotiated transactions. If the applicable prospectus supplement indicates, in connection with
those sale, forward sale or derivative transactions, the third parties may sell securities covered by this prospectus and the applicable prospectus supplement, including in short sale transactions and by issuing securities that are not covered by
this prospectus but are exchangeable for or represent beneficial interests in the common stock. The third parties also may use shares received under those sale, forward sale or derivative arrangements or shares pledged by the selling securityholder
or borrowed from the selling securityholders or others to settle such third-party sales or to close out any related open borrowings of common stock. The third parties may deliver this prospectus in connection with any such transactions. Any third
party in such sale transactions will be an underwriter and will be identified in the applicable prospectus supplement (or a post-effective amendment to the registration statement of which this prospectus is a part). 

In addition, the selling securityholders may engage in hedging transactions with broker-dealers in connection with distributions of Securities
or otherwise. In those transactions, broker-dealers may engage in short sales of securities in the course of hedging the positions they assume with selling securityholders. The selling securityholders may also sell securities short and redeliver
securities to close out such short positions. The selling securityholders may also enter into option or other transactions with broker-dealers which require the delivery of securities to the broker-dealer. The broker-dealer may then resell or
otherwise transfer such securities pursuant to this prospectus. The selling securityholders also may loan or pledge shares, and the borrower or pledgee may sell or otherwise transfer the Securities so loaned or pledged pursuant to this prospectus.
Such borrower or pledgee also may transfer those Securities to investors in our securities or the selling securityholders’ securities or in connection with the offering of other securities not covered by this prospectus. 






 To the extent necessary, we may amend or supplement this prospectus from time to time to describe
a specific plan of distribution. We will file a supplement to this prospectus, if required, upon being notified by the selling securityholders that any material arrangement has been entered into with a broker-dealer for the sale of shares through a
block trade, offering or a purchase by a broker or dealer. The applicable prospectus supplement will set forth the specific terms of the offering of securities, including: 
  

	 	•	 	the number of Securities offered; 

  

	 	•	 	the price of such Securities; 

  

	 	•	 	the proceeds to the selling securityholders from the sale of such Securities; 

  

	 	•	 	the names of the underwriters or agents, if any; 

  

	 	•	 	any underwriting discounts, agency fees or other compensation to underwriters or agents; and 

  

	 	•	 	any discounts or concessions allowed or paid to dealers. 

 The selling securityholders may, or
may authorize underwriters, dealers and agents to, solicit offers from specified institutions to purchase Securities from the selling securityholders at the public offering price listed in the applicable prospectus supplement. These sales may be
made under “delayed delivery contracts” or other purchase contracts that provide for payment and delivery on a specified future date. Any contracts like this will be described in and be subject to the conditions listed in the applicable
prospectus supplement. 
 Broker-dealers or agents may receive compensation in the form of commissions, discounts or concessions from the
selling securityholders. Broker-dealers or agents may also receive compensation from the purchasers of Securities for whom they act as agents or to whom they sell as principals, or both. Compensation as to a particular broker-dealer might be in
excess of customary commissions and will be in amounts to be negotiated in connection with transactions involving securities. In effecting sales, broker-dealers engaged by the selling securityholders may arrange for other broker-dealers to
participate in the resales. 
 In connection with sales of Securities covered hereby, the selling securityholders and any underwriter,
broker-dealer or agent and any other participating broker-dealer that executes sales for the selling securityholders may be deemed to be an “underwriter” within the meaning of the Securities Act of 1933, as amended (the
“Securities Act”). Accordingly, any profits realized by the selling securityholders and any compensation earned by such underwriter, broker-dealer or agent may be deemed to be underwriting discounts and commissions. Because
the selling securityholders may be deemed to be “underwriters” under the Securities Act, the selling securityholders must deliver this prospectus and any prospectus supplement in the manner required by the Securities Act. This prospectus
delivery requirement may be satisfied through the facilities of the NYSE MKT LLC in accordance with Rule 153 under the Securities Act or satisfied in accordance with Rule 174 under the Securities Act. 






 We and the selling securityholders have agreed to indemnify each other against certain
liabilities, including liabilities under the Securities Act. In addition, we or the selling securityholders may agree to indemnify any underwriters, broker-dealers and agents against or contribute to any payments the underwriters, broker-dealers or
agents may be required to make with respect to, civil liabilities, including liabilities under the Securities Act. Underwriters, broker-dealers and agents and their affiliates are permitted to be customers of, engage in transactions with, or perform
services for us and our affiliates or the selling securityholders or their affiliates in the ordinary course of business. 
 The selling
securityholders will be subject to applicable provisions of Regulation M of the Securities Exchange Act of 1934 and the rules and regulations thereunder, which provisions may limit the timing of purchases and sales of any of the Securities by the
selling securityholders. Regulation M may also restrict the ability of any person engaged in the distribution of the Securities to engage in market-making activities with respect to the Securities. These restrictions may affect the marketability of
such Securities. 
 In order to comply with applicable securities laws of some states, the Securities may be sold in those jurisdictions
only through registered or licensed brokers or dealers. In addition, in certain states the Securities may not be sold unless they have been registered or qualified for sale in the applicable state or an exemption from the registration or
qualification requirements is available. In addition, any Securities of a selling securityholder covered by this prospectus that qualify for sale pursuant to Rule 144 under the Securities Act may be sold in open market transactions under Rule 144
rather than pursuant to this prospectus. 
 In connection with an offering of Securities under this prospectus, the underwriters may
purchase and sell securities in the open market. These transactions may include short sales, stabilizing transactions and purchases to cover positions created by short sales. Short sales involve the sale by the underwriters of a greater number of
securities than they are required to purchase in an offering. Stabilizing transactions consist of certain bids or purchases made for the purpose of preventing or retarding a decline in the market price of the securities while an offering is in
progress. 
 The underwriters also may impose a penalty bid. This occurs when a particular underwriter repays to the underwriters a portion
of the underwriting discount received by it because the underwriters have repurchased securities sold by or for the account of that underwriter in stabilizing or short-covering transactions. 

These activities by the underwriters may stabilize, maintain or otherwise affect the market price of the Securities offered under this
prospectus. As a result, the price of the Securities may be higher than the price that otherwise might exist in the open market. If these activities are commenced, they may be discontinued by the underwriters at any time. These transactions may be
effected on the NYSE MKT LLC or another securities exchange or automated quotation system, or in the over-the-counter market or otherwise. 






 EXHIBIT A 

FORM OF 
 SELLING
SECURITYHOLDER QUESTIONNAIRE 
 Reference is made to that certain registration rights agreement (the “Registration Rights
Agreement”), dated as of March 3, 2017, by and between Gastar Exploration Inc. (the “Company”) and each of the purchasers listed on Schedule I thereto. Capitalized terms used and not defined herein shall
have the meanings given to such terms in the Registration Rights Agreement. 
 The undersigned Holder (the “Selling Securityholder”)
of the Registrable Securities is providing this Selling Securityholder Questionnaire pursuant to Section 3(k) of the Registration Rights Agreement. The Selling Securityholder, by signing and returning this Selling Securityholder Questionnaire,
understands that it will be bound by the terms and conditions of this Selling Securityholder Questionnaire and the Registration Rights Agreement. The Selling Securityholder hereby acknowledges its indemnity obligations pursuant to Section 5(b) of
the Registration Rights Agreement. 
 The Selling Securityholder provides the following information to the Company and represents and warrants that such
information is accurate and complete: 
  

							
	(1)	  	(a)	    	Full Legal Name of Selling Securityholder:	  	
				
		  		    	  
	  	
		  	(b)	    	Full Legal Name of Registered Holder (if not the same as (a) above) through which Registrable Securities listed in (3) below are held:
				
		  		    	  
	  	
		  	(c)	    	Full Legal Name of DTC Participant (if applicable and if not the same as (b) above) through which Registrable Securities listed in (3) below are held:
				
		  		    	  
	  	
		
	(2)	  	Address for Notices to Selling Securityholder:
				
		  		    	  
	  	
		  		    	  
	  	

 Telephone (including area code):
                                         
                      
 Fax (including area
code):
                                         
                                 

Contact Person:
                                         
                                         
        
  

	(3)	Beneficial Ownership of Registrable Securities: 


                          
                                         
                                         
                           
  

	(a)	Type and Principal Amount/Number of Registrable Securities beneficially owned: 


                          
                                         
                                         
                           
  

	(b)	CUSIP No(s). of such Registrable Securities beneficially owned: 


                          
                                         
                                         
                           







	(4)	Beneficial Ownership of Other Securities of the Company Owned by the Selling Securityholder with Respect to Which Item 403 or Item 507 of Regulation S-K Requires Disclosure in the
Prospectus to Which This Questionnaire Relates (“Other Securities”): 

 Except as set forth below in
this Item (4), the Selling Securityholder is not the beneficial or registered owner of any Other Securities of the Company other than the Registrable Securities listed above in Item (3). 

 

	 	(a)	Type and Amount of Other Securities beneficially owned by the Selling Securityholder: 


	 	    	                                    
                                         
        

  

	(b)	CUSIP No(s). of such Other Securities beneficially owned: 

  

	(5)	Relationship with the Company: 

 Except as set forth below, neither the Selling
Securityholder nor any of its affiliates, officers, directors or principal equity holders (5% or more) has held any position or office or has had any other material relationship with the Company (or its predecessors or affiliates) during the past
three years. 
 State any exceptions here: 
  

	(6)	Is the Selling Securityholder a registered broker-dealer? 

  

	Yes	☐ 


	No	☐ 

 If “Yes”, please answer subsection (a) and subsection (b): 

(a) Did the Selling Securityholder acquire the Registrable Securities as compensation for underwriting/broker-dealer activities to the
Company? 
 Yes     ☐ 

No      ☐ 

(b) If you answered “No” to question 6(a), please explain your reason for acquiring the Registrable Securities: 

                       
                                         
                                         
                                         
       

                       
                                         
                                         
                                         
       
  

	(7)	Is the Selling Securityholder an affiliate of a registered broker-dealer? 

  

	Yes	☐ 


	No	☐ 

 If “Yes”, please identify the registered broker-dealer(s), describe the
nature of the affiliation(s) and answer subsection (a) and subsection (b): 

                          
                                         
                                         
             

                          
                                         
                                         
             
 (a) Did the Selling Securityholder purchase the Registrable
Securities in the ordinary course of business (if no, please explain)? 
 Yes     ☐ 

No      ☐ 






 Explain: 

                          
                                         
                                         
             

                         
                                         
                                         
              
 (b) Did the Selling Securityholder have an
agreement or understanding, directly or indirectly, with any person to distribute the Registrable Securities at the same time the Registrable Securities were originally purchased (if yes, please explain)? 

Yes    ☐ 

No     ☐ 

Explain: 
  

	(8)	Is the Selling Securityholder a non-public entity? 

  

	Yes	☐ 


	No	☐ 

 If “Yes”, please answer subsection (a): 

(a) Identify the natural person or persons that have voting or investment control over the Registrable Securities that the non-public entity owns: 
  

	(9)	Plan of Distribution: 

 The Selling Securityholder (including its donees and pledgees) intends to distribute
the Registrable Securities listed above in Item (3) pursuant to the Registration Statement in accordance with [the Plan of Distribution attached as Annex A to the Registration Rights Agreement]  ☐. 

The Selling Securityholder acknowledges that it understands its obligations to comply with the provisions of the Securities Exchange Act of 1934, as amended,
and the rules thereunder relating to stock manipulation, particularly Regulation M thereunder (or any successor rules or regulations), in connection with any offering of Registrable Securities pursuant to the Shelf Registration Agreement. The
Selling Securityholder agrees that neither it nor any person acting on its behalf will engage in any transaction in violation of such provisions. 

Pursuant to the Registration Rights Agreement, the Company has agreed under certain circumstances to indemnify the Selling Securityholder against certain
liabilities. 
 In the event the Selling Securityholder transfers all or any portion of the Registrable Securities listed in Item (3) above after the
date on which such information is provided to the Company such that such securities remain Registrable Securities under the Registration Rights Agreement, the Selling Securityholder agrees to notify the transferee(s) at the time of the transfer of
its rights and obligations under this Selling Securityholder Questionnaire and the Registration Rights Agreement. 
 In accordance with the Selling
Securityholder’s obligation under the Registration Rights Agreement to provide such information as may be required by law or by the staff of the Commission for inclusion in the Registration Statement, the Selling Securityholder agrees to
promptly notify the Company of any inaccuracies or changes in the information provided herein that may occur subsequent to the date hereof at any time while the Registration Statement remains effective. All notices to the Selling Securityholder
pursuant to the Registration Rights Agreement shall be made in writing, by hand-delivery, first-class mail, or air courier guaranteeing overnight delivery to the address set forth below. 






 By signing below, the Selling Securityholder consents to the disclosure of the information contained herein in
its answers to Items (1) through (9) above and the inclusion of such information in the Registration Statement and the related Prospectus. The undersigned understands that such information will be relied upon by the Company in connection with
the preparation or amendment of the Registration Statement and the related Prospectus. 
 By signing below, the undersigned agrees that if the Company
notifies the undersigned that the Registration Statement is not available pursuant to the terms of the Registration Rights Agreement, the undersigned will suspend use of the Prospectus until notice from the Company that the Prospectus is again
available. 
 Once this Selling Securityholder Questionnaire is executed by the undersigned and received by the Company, the terms of this Selling
Securityholder Questionnaire, and the representations, warranties and agreements contained herein, shall be binding on, shall inure to the benefit of and shall be enforceable by the respective successors, heirs, personal representatives, and assigns
of the Company and the undersigned with respect to the Registrable Securities beneficially owned by the undersigned and listed in Item (3) above. This Selling Securityholder Questionnaire shall be governed by and construed in accordance with
the laws of the State of New York without regard to choice of laws or conflicts of laws provisions thereof that would require the application of the laws of any other jurisdiction. 






 IN WITNESS WHEREOF, the undersigned, by authority duly given, has caused this Selling
Securityholder Questionnaire to be executed and delivered either in person or by its duly authorized agent. 
 Dated:
                     
  

			
	  

	 Beneficial Owner

	 By:
	 	  

	 Name:
	 	  

	 Title:
	 	  



 PLEASE RETURN THE COMPLETED AND EXECUTED 

SELLING SECURITYHOLDER QUESTIONNAIRE TO THE COMPANY AT: 

Gastar Exploration Inc. 
 1331
Lamar Street, Suite 650 
 Houston, TX 77010 

Attention:     Chief Executive Officer and Chief Financial Officer 

E-mail:         rporter@gastar.com; mgerlich@gastar.com