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                                                                     EXHIBIT 3.1






                AMENDED AND RESTATED CERTIFICATE OF INCORPORATION

                                       OF

                            ALLEGIANCE TELECOM, INC.



                                ARTICLE I - Name

         The name of the corporation is Allegiance Telecom, Inc. (hereinafter
referred to as the "Corporation").

                         ARTICLE II - Registered Office

         The address of the registered office of the Corporation in the State of
Delaware is 1209 Orange Street, in the City of Wilmington, County of New Castle,
Delaware 19801. The name of the registered agent of the Corporation at that
address is The Corporation Trust Company.

                              ARTICLE III - Purpose

         The purpose of the Corporation is to engage in any lawful act or
activity for which corporations may be organized under the General Corporation
Law of the State of Delaware (the "Delaware General Corporation Law").

                           ARTICLE IV - Capital Stock

         Part A.    General. The maximum number of shares of capital stock that
the Corporation is authorized to have outstanding at any one time is 151,000,000
shares, consisting of: (i) 1,000,000 shares of Preferred Stock, par value $0.01
per share (the "Preferred Stock"); and (ii) 150,000,000 shares of Common Stock,
par value $0.01 per share (the "Common Stock").

         Part B.    Preferred Stock. Authority is hereby expressly vested in the
Board of Directors of the Corporation (each member thereof, a "Director," and
collectively, the "Board of Directors" or the "Board"), without further action
by the Corporation's stockholders, subject to the provisions of this ARTICLE IV
and to the limitations prescribed by law, to authorize the issuance from time to
time of one or more series of Preferred Stock. The authority of the Board of
Directors with respect to each series shall include, but not be limited to, the
determination or fixing of the following by resolution or resolutions adopted by
the affirmative vote of a majority of the total number of the Directors then in
office:




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         (1)   The designation of such series;

         (2)   The dividend rate of such series, the conditions and dates upon
which such dividends shall be payable, the relation which such dividends shall
bear to the dividends payable on any other class or classes or series of the
Corporation's capital stock and whether such dividends shall be cumulative or
non-cumulative;

         (3)   Whether the shares of such series shall be subject to redemption
for cash, property or rights, including securities of any other corporation, by
the Corporation or upon the happening of a specified event and, if made subject
to any such redemption, the times or events, prices, rates, adjustments and
other terms and conditions of such redemptions;

         (4)   The terms and amount of any sinking fund provided for the
purchase or redemption of the shares of such series;

         (5)   Whether or not the shares of such series shall be convertible
into, or exchangeable for, at the option of either the holder or the Corporation
or upon the happening of a specified event, shares of any other class or classes
or of any other series of the same class of the Corporation's capital stock and,
if provision be made for conversion or exchange, the times or events, prices,
rates, adjustments and other terms and conditions of such conversions or
exchanges;

         (6)   The restrictions, if any, on the issue or reissue of any
additional Preferred Stock;

         (7)   The rights of the holders of the shares of such series upon the
voluntary or involuntary liquidation, dissolution or winding up of the
Corporation; and

         (8)   The provisions as to voting, optional and/or other special rights
and preferences, if any, including, without limitation, the right to elect one
or more Directors.

         Part C.    Common Stock. Except as otherwise provided by the Delaware
General Corporation Law or this Restated Certificate of Incorporation (the
"Restated Certificate"), and subject to the rights of holders of any series of
Preferred Stock, the holders of record of Common Stock shall share ratably in
all dividends payable in cash, stock or otherwise and other distributions,
whether in respect of liquidation or dissolution (voluntary or involuntary) or
otherwise and, are subject to all the powers, rights, privileges, preferences
and priorities of any series of Preferred Stock as provided herein or in any
resolution or resolutions adopted by the Board of Directors pursuant to
authority expressly vested in it by the provisions of Section B of this ARTICLE
IV.

         (1)   The Common Stock shall not be convertible into, or exchangeable
for, shares of any other class or classes or of any other series of the same of
the Corporation's capital stock.

         (2)   No holder of Common Stock shall have any preemptive,
subscription, redemption, conversion or sinking fund rights with respect to the
Common Stock, or to any



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obligations convertible (directly or indirectly) into stock of the Corporation
whether now or hereafter authorized.

         (3)   Except as otherwise provided by the Delaware General Corporation
Law, or the Restated Certificate and subject to the rights of holders of any
series of Preferred Stock, all of the voting power of the stockholders of the
Corporation shall be vested in the holders of the Common Stock, and each holder
of Common Stock shall have one vote for each share held by such holder on all
matters voted upon by the stockholders of the Corporation.


                              ARTICLE V - Existence

         The Corporation is to have perpetual existence.


                              ARTICLE VI - By-laws

         In furtherance and not in limitation of the powers conferred by the
Delaware General Corporation Law, the Board of Directors of the Corporation is
expressly authorized to make, alter, amend, change, add to or repeal the By-laws
of the Corporation by the affirmative vote of a majority of the total number of
Directors then in office. Any alteration or repeal of the By-laws of the
Corporation by the stockholders of the Corporation shall require the affirmative
vote of at least a majority of the voting power of the then outstanding shares
of capital stock of the Corporation entitled to vote on such alteration or
repeal, subject to ARTICLE IX hereof and ARTICLE VII of the Corporation's
By-laws.


                    ARTICLE VII - Stockholders and Directors

         Part A.    Stockholder Action. Election of Directors need not be by
written ballot unless the By-laws of the Corporation so provide. Subject to any
rights of holders of any series of Preferred Stock, from and after the date on
which the Common Stock of the Corporation is registered pursuant to the
Securities Exchange Act of 1934, as amended (the "Exchange Act"), (i) any action
required or permitted to be taken by the stockholders of the Corporation must be
effected at an annual or special meeting of stockholders of the Corporation and
may not be effected in lieu thereof by any consent in writing by such
stockholders, (ii) special meetings of stockholders of the Corporation may be
called only by either the Board of Directors pursuant to a resolution adopted by
the affirmative vote of the majority of the total number of Directors then in
office or by the chief executive officer of the Corporation and (iii) advance
notice of stockholder nominations of persons for election to the Board of
Directors of the Corporation and of business to be brought before any annual
meeting of the stockholders by the stockholders of the Corporation shall be
given in the manner provided in the By-laws of the Corporation.

         Part B.    Number of Directors and Term of Office. Subject to any
rights of holders of any series of Preferred Stock to elect additional Directors
under specified circumstances, the number of Directors which shall constitute
the Board of Directors of the Corporation shall be




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fixed from time to time in the manner set forth in the By-laws of the
Corporation. The Directors of the Corporation shall be divided into three
classes: Class I, Class II and Class III. Membership in each such class shall be
as nearly equal in number as possible. The term of office of the initial Class I
Directors shall expire at the annual election of Directors by the stockholders
of the Corporation in 1999, the term of office of the initial Class II Directors
shall expire at the annual election of Directors by the stockholders of the
Corporation in 2000 and the term of office of the initial Class III Directors
shall expire at the annual election of Directors by the stockholders of the
Corporation in 2001, or thereafter when their respective successors in each case
are elected by the stockholders and qualified, subject however, to prior death,
resignation, retirement, disqualification or removal from office for cause. At
each succeeding annual election of Directors by the stockholders of the
Corporation beginning in 1999, the Directors chosen to succeed those whose terms
then expire shall be identified as being of the same class as the Directors they
succeed and shall be elected for a term expiring at the third succeeding annual
election of Directors by the stockholders of the Corporation, or thereafter when
their respective successors in each case are elected by the stockholders and
qualified. If the number of Directors is changed, any increase or decrease shall
be apportioned among the classes so as to maintain the number of Directors in
each class as nearly equal as possible, and any additional Director of any class
elected to fill a vacancy resulting from an increase in such class shall hold
office for a term that shall coincide with the remaining term of that class, but
in no case shall a decrease in the number of Directors shorten the term of any
incumbent Director.

         Part C.    Removal and Resignation. No Director may be removed from
office without cause and without the affirmative vote of the holders of a
majority of the voting power of the then outstanding shares of capital stock of
the Corporation entitled to vote generally in the election of Directors voting
together as a single class; provided, however, that if the holders of any class
or series of capital stock are entitled by the provisions of this Restated
Certificate (it being understood that any references to this Restated
Certificate shall include any duly authorized certificate of designation) to
elect one or more Directors, such Director or Directors so elected may be
removed without cause only by the vote of the holders of a majority of the
outstanding shares of that class or series entitled to vote. Any Director may
resign at any time upon written notice to the Corporation.

         Part D.    Vacancies and Newly Created Directorships. Subject to any
rights of holders of any series of Preferred Stock to fill such newly created
Directorships or vacancies, any newly created Directorships resulting from any
increase in the authorized number of Directors and any vacancies in the Board of
Directors resulting from death, resignation, disqualification or removal from
office for cause shall, unless otherwise provided by law or by resolution
approved by the affirmative vote of a majority of the total number of Directors
then in office, be filled only by resolution approved by the affirmative vote of
a majority of the total number of Directors then in office. Any Director so
chosen shall hold office until the next election of the class for which such
Director shall have been chosen, and until his successor shall have been duly
elected and qualified, unless he shall resign, die, become disqualified or be
removed for cause.




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                        ARTICLE VIII - General Provisions

         Part A.    Dividends. The Board of Directors shall have authority from
time to time to set apart out of any assets of the Corporation otherwise
available for dividends a reserve or reserves as working capital or for any
other purpose or purposes, and to abolish or add to any such reserve or reserves
from time to time as said board may deem to be in the interest of the
Corporation; and said Board shall likewise have power to determine in its
discretion, except as herein otherwise provided, what part of the assets of the
Corporation available for dividends in excess of such reserve or reserves shall
be declared in dividends and paid to the stockholders of the Corporation.

         Part B.    Issuance of Stock. The shares of all classes of stock of the
Corporation may be issued by the Corporation from time to time for such
consideration as from time to time may be fixed by the Board of Directors of the
Corporation, provided that shares of stock having a par value shall not be
issued for a consideration determined by the Board to be less than such par
value. At any time, or from time to time, the Corporation may grant rights or
options to purchase from the Corporation any shares of its stock of any class or
classes to run for such period of time, for such consideration, upon such terms
and conditions, and in such form as the Board of Directors may determine. The
Board of Directors shall have authority, as provided by law, to determine that
only a part of the consideration which shall be received by the Corporation for
the shares of its stock which it shall issue from time to time, shall be
capital; provided, however, that, if all the shares issued shall be shares
having a par value, the amount of the part of such consideration so determined
to be capital shall be equal to the aggregate par value of such shares. The
excess, if any, at any time, of the total net assets of the Corporation over the
amount so determined to be capital, as aforesaid, shall be surplus. All classes
of stock of the Corporation shall be and remain at all times nonassessable.

         The Board of Directors is hereby expressly authorized, in its
discretion, in connection with the issuance of any obligations or stock of the
Corporation (but without intending hereby to limit its general power so to do in
other cases), to grant rights or options to purchase stock of the Corporation of
any class upon such terms and during such period as the Board of Directors shall
determine, and to cause such rights to be evidenced by such warrants or other
instruments as it may deem advisable.

         Part C.    Inspection of Books and Records. The Board of Directors
shall have power from time to time to determine to what extent and at what times
and places and under what conditions and regulations the accounts and books of
the Corporation, or any of them, shall be open to the inspection of the
stockholders; and no stockholder shall have any right to inspect any account or
book or document of the Corporation, except as conferred by the laws of the
State of Delaware, unless and until authorized so to do by resolution of the
Board of Directors or of the stockholders of the Corporation.

         Part D.    Location of Meetings, Books and Records. Except as otherwise
provided in the By-laws, the stockholders of the Corporation and the Board of
Directors may hold their meetings and have an office or offices outside of the
State of Delaware and, subject to the provisions of the laws of said State, may
keep the books of the Corporation outside of said State at such places as may,
from time to time, be designated by the Board of Directors.




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                             ARTICLE IX - Amendments

         The Corporation reserves the right to amend, alter, change or repeal
any provision contained in this Restated Certificate in the manner now or
hereinafter prescribed herein and by the laws of the State of Delaware, and all
rights conferred upon stockholders herein are granted subject to this
reservation. Notwithstanding anything contained in this Restated Certificate to
the contrary, ARTICLE IV, ARTICLE VII, ARTICLE X, and this ARTICLE IX of this
Restated Certificate shall not be altered, amended or repealed and no provision
inconsistent therewith shall be adopted without the affirmative vote of the
holders of at least 66 2/3% of the voting power of the then outstanding shares
of capital stock of the Corporation entitled to vote on such alteration,
amendment or repeal, voting together as a single class (other than any
alteration or amendment to Part A of ARTICLE IV that increases the authorized
number of shares of Preferred Stock or Common Stock).


                              ARTICLE X - Liability

         Part A.    Limitation of Liability.

         (1)   To the fullest extent permitted by the Delaware General
Corporation Law as it now exists or may hereafter be amended (but, in the case
of any such amendment, only to the extent that such amendment permits the
Corporation to provide broader indemnification rights than permitted prior
thereto), and except as otherwise provided in the Corporation's By-laws, no
Director of the Corporation shall be liable to the Corporation or its
stockholders for monetary damages arising from a breach of fiduciary duty owed
to the Corporation or its stockholders.

         (2)   Any repeal or modification of the foregoing paragraph by the
stockholders of the Corporation shall not adversely affect any right or
protection of a Director of the Corporation existing at the time of such repeal
or modification.

         Part B.    Right to Indemnification. Each person who was or is made a
party or is threatened to be made a party to or is otherwise involved (including
involvement as a witness) in any action, suit or proceeding, whether civil,
criminal, administrative or investigative (a "proceeding"), by reason of the
fact that he or she is or was a Director or officer of the Corporation or, while
a Director or officer of the Corporation, is or was serving at the request of
the Corporation as a Director, officer, employee or agent of another corporation
or of a partnership, joint venture, trust or other enterprise, including service
with respect to an employee benefit plan (an "indemnitee"), whether the basis of
such proceeding is alleged action in an official capacity as a Director or
officer or in any other capacity while serving as a Director or officer, shall
be indemnified and held harmless by the Corporation to the fullest extent
authorized by the Delaware General Corporation Law, as the same exists or may
hereafter be amended (but, in the case of any such amendment, only to the extent
that such amendment permits the Corporation to provide broader indemnification
rights than permitted prior thereto), against all expense, liability and loss
(including attorneys' fees, judgments, fines, excise exercise taxes or penalties
and amounts paid in settlement) reasonably incurred or suffered by such
indemnitee in connection therewith and such indemnification




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shall continue as to an indemnitee who has ceased to be a Director, officer,
employee or agent and shall inure to the benefit of the indemnitee's heirs,
executors and administrators; provided, however, that, except as provided in
Part C of this ARTICLE X with respect to proceedings to enforce rights to
indemnification, the Corporation shall indemnify any such indemnitee in
connection with a proceeding (or part thereof) initiated by such indemnitee only
if such proceeding (or part thereof) was authorized by the Board of Directors of
the Corporation. The right to indemnification conferred in this Part B of this
ARTICLE X shall be a contract right and shall include the obligation of the
Corporation to pay the expenses incurred in defending any such proceeding in
advance of its final disposition (an "advance of expenses"); provided, however,
that, if and to the extent that the Delaware General Corporation Law requires,
an advance of expenses incurred by an indemnitee in his or her capacity as a
Director or officer (and not in any other capacity in which service was or is
rendered by such indemnitee, including, without limitation, service to an
employee benefit plan) shall be made only upon delivery to the Corporation of an
undertaking (an "undertaking"), by or on behalf of such indemnitee, to repay all
amounts so advanced if it shall ultimately be determined by final judicial
decision from which there is no further right to appeal (a "final adjudication")
that such indemnitee is not entitled to be indemnified for such expenses under
this Part B or otherwise. The Corporation may, by action of its Board of
Directors, provide indemnification to employees and agents of the Corporation
with the same or lesser scope and effect as the foregoing indemnification of
Directors and officers.

         Part C.    Procedure for Indemnification. Any indemnification of a
Director or officer of the Corporation or advance of expenses under Part B of
this ARTICLE X shall be made promptly, and in any event within forty-five days
(or, in the case of an advance of expenses, twenty days), upon the written
request of the Director or officer. If a determination by the Corporation that
the Director or officer is entitled to indemnification pursuant to this ARTICLE
X is required, and the Corporation fails to respond within sixty days to a
written request for indemnity, the Corporation shall be deemed to have approved
the request. If the Corporation denies a written request for indemnification or
advance of expenses, in whole or in part, or if payment in full pursuant to such
request is not made within forty-five days (or, in the case of an advance of
expenses, twenty days), the right to indemnification or advances as granted by
this ARTICLE X shall be enforceable by the Director or officer in any court of
competent jurisdiction. Such person's costs and expenses incurred in connection
with successfully establishing his or her right to indemnification, in whole or
in part, in any such action shall also be indemnified by the Corporation. It
shall be a defense to any such action (other than an action brought to enforce a
claim for the advance of expenses where the undertaking required pursuant to
Part B of this ARTICLE X, if any, has been tendered to the Corporation) that the
claimant has not met the standards of conduct which make it permissible under
the Delaware General Corporation Law for the Corporation to indemnify the
claimant for the amount claimed, but the burden of such defense shall be on the
Corporation. Neither the failure of the Corporation (including its Board of
Directors, independent legal counsel or its stockholders) to have made a
determination prior to the commencement of such action that indemnification of
the claimant is proper in the circumstances because he or she has met the
applicable standard of conduct set forth in the Delaware General Corporation
Law, nor an actual determination by the Corporation (including its Board of
Directors, independent legal counsel or its stockholders) that the claimant has
not met such applicable standard of conduct, shall be a defense to the action or
create a presumption that the claimant has not met the applicable standard of
conduct. The procedure for indemnification of other employees and agents for
whom indemnification is provided pursuant to Part B of this ARTICLE




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X shall be the same procedure set forth in this Part C for Directors or
officers, unless otherwise set forth in the action of the Board of Directors
providing indemnification for such employee or agent.

         Part D.    Insurance. The Corporation may purchase and maintain
insurance on its own behalf and on behalf of any person who is or was a
Director, officer, employee or agent of the Corporation or was serving at the
request of the Corporation as a Director, officer, employee or agent of another
corporation, partnership, joint venture, trust or other enterprise against any
expense, liability or loss asserted against him or her and incurred by him or
her in any such capacity, whether or not the Corporation would have the power to
indemnify such person against such expenses, liability or loss under the
Delaware General Corporation Law.

         Part E.    Service for Subsidiaries. Any person serving as a Director,
officer, employee or agent of another corporation, partnership, limited
liability company, joint venture or other enterprise, at least 50% of whose
equity interests are owned directly or indirectly by the Corporation (a
"subsidiary" for this ARTICLE X) shall be conclusively presumed to be serving in
such capacity at the request of the Corporation.

         Part F.    Reliance. Persons who after the date of the adoption of this
provision become or remain Directors or officers of the Corporation or who,
while a Director or officer of the Corporation, become or remain a Director,
officer, employee or agent of a subsidiary, shall be conclusively presumed to
have relied on the rights to indemnity, advance of expenses and other rights
contained in this ARTICLE X in entering into or continuing such service. The
rights to indemnification and to the advance of expenses conferred in this
ARTICLE X shall apply to claims made against an indemnitee arising out of acts
or omissions which occurred or occur both prior and subsequent to the adoption
hereof.

         Part G.    Non-Exclusivity of Rights. The rights to indemnification and
to the advance of expenses conferred in this ARTICLE X shall not be exclusive of
any other right which any person may have or hereafter acquire under this
Restated Certificate or under any statute, by-law, agreement, vote of
stockholders or disinterested Directors or otherwise.

         Part H.    Merger or Consolidation. For purposes of this ARTICLE X,
references to the "Corporation" shall include, in addition to the resulting
Corporation, any constituent Corporation (including any constituent of a
constituent) absorbed in a consolidation or merger which, if its separate
existence had continued, would have had power and authority to indemnify its
Directors, officers and employees or agents, so that any person who is or was a
Director, officer, employee or agent of such constituent Corporation, or is or
was serving at the request of such constituent Corporation as a Director,
officer, employee or agent of another Corporation, partnership, limited
liability company, joint venture, trust or other enterprise, shall stand in the
same position under this ARTICLE X with respect to the resulting or surviving
Corporation as he or she would have with respect to such constituent Corporation
if its separate existence had continued.

                       ARTICLE XI - Business Combinations

         The Corporation expressly elects to be governed by Section 203 of the
Delaware General Corporation Law.

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