<PAGE>

                                                                     EXHIBIT 3.2

                          AMENDED AND RESTATED BYLAWS

                                       OF

                     NORTHPOINT COMMUNICATIONS GROUP, INC.
<PAGE>

                                   ARTICLE I

                               CORPORATE OFFICES
                               -----------------

1.1  Registered Office.
     -----------------

     The registered office of the corporation shall be in the City of
Wilmington, County of New Castle, State of Delaware. The name of the registered
agent of the corporation at such location is The Corporation Trust Company.

1.2  Other Offices.
     -------------

     The board of directors may at any time establish other offices at any place
or places where the corporation is qualified to do business.

                                   ARTICLE II

                            MEETINGS OF STOCKHOLDERS
                            ------------------------

2.1  Place of Meetings.
     -----------------

     Meetings of stockholders shall be held at any place, within or outside the
State of Delaware, designated by the Board of Directors. In the absence of any
such designation, stockholders' meetings shall be held at the registered office
of the corporation.

2.2  Annual Meeting.
     --------------

     The annual meeting of stockholders shall be held each year on a date and at
a time designated by the board of directors. At the meeting, directors shall be
elected and any other proper business may be transacted.

2.3  Special Meeting.
     ---------------

     A special meeting of the stockholders may be called at any time by the
board of directors, or by the chairman of the board, or by the chief executive
officer or the president or vice president of the corporation.

2.4  Notice of Stockholders' Meetings.
     --------------------------------

     All notices of meetings with stockholders shall be in writing and shall be
sent or otherwise given in accordance with Section 2.7 of these bylaws not less
than ten (10) nor more than sixty (60) days before the date of the meeting to
each stockholder entitled to vote at such meeting. The notice shall specify the
place, date, and hour of the meeting,

                                       2
<PAGE>

and, in the case of a special meeting, the purpose or purposes for which the
meeting is called.

2.5  Advance Notice of Stockholder Nominees.
     --------------------------------------

     Only persons who are nominated in accordance with the procedures set forth
in this Section 2.5 shall be eligible for election as directors. Nominations of
persons for election to the board of directors of the corporation may be made at
a meeting of stockholders by or at the direction of the board of directors or by
any stockholder of the corporation entitled to vote for the election of
directors at the meeting who complies with the notice procedures set forth in
this Section 2.5. Such nominations, other than those made by or at the direction
of the board of directors, shall be made pursuant to timely notice in writing to
the secretary of the corporation.

     To be timely, a stockholder's notice shall be delivered to or mailed and
received at the principal executive offices of the corporation (a) in the case
of an annual meeting, not less than sixty (60) days nor more than ninety (90)
days prior to the first anniversary of the preceding year's annual meeting;
provided, however, that in the event that the date of the annual meeting is
changed by more than thirty (30) days from such anniversary date, notice by the
stockholders to be timely must be so received not later than the close of
business on the tenth (10th) day following the earlier of the day on which such
notice of the date of the meeting was mailed or public disclosure was made and
(b) in the case of a special meeting at which directors are to be elected, not
later than the close of business on the tenth (10th) day following the earlier
of the day on which notice of the date of the meeting was mailed or public
disclosure was made. Such stockholder's notice shall set forth (a) as to each
person whom the stockholder proposes to nominate for election or re-election as
a director, (i) the name, age, business address and residence address of such
person, (ii) the principal occupation or employment of such person, (iii) the
class and number of shares of the corporation which are beneficially owned by
such person and (iv) any other information relating to such person that is
required to be disclosed in solicitations of proxies for election of directors,
or is otherwise required, in each case pursuant to Regulation 14A under the
Securities Exchange Act of 1934, as amended (including, without limitation, such
person's written consent to being named in the proxy statement as a nominee and
to serving as a director if elected, and (b) as to the stockholder giving the
notice, (i) the name and address, as they appear on the corporation's books, of
such stockholder, and (ii) the class and number of shares of the corporation
which are beneficially owned by such stockholder and also which are owned of
record by such stockholder.

     At the request of the board of directors, any person nominated by the board
of directors for election as a director shall furnish to the secretary of the
corporation that information required to be set forth in a stockholder's notice
of nomination which pertains to the nominee. No person shall be eligible for
election as a director of the corporation unless nominated in accordance with
the procedures set forth in this Section 2.5. The chairman of the meeting shall,
if the facts warrant, determine and

                                       3
<PAGE>

declare to the meeting that a nomination was not made in accordance with the
procedures prescribed by the bylaws, and, if he or she should so determine, he
or she shall so declare to the meeting and the defective nomination shall be
disregarded. Notwithstanding the foregoing provisions of this Bylaw, a
stockholder shall also comply with all applicable requirements of the Securities
Exchange Act of 1934, as amended, and the rules and regulations thereunder with
respect to the matters set forth in this Bylaw.

2.6  Advance Notice of Stockholder Business.
     --------------------------------------

     At an annual meeting of the stockholders, only such business shall be
conducted as shall have been properly brought before the annual meeting. To be
properly brought before an annual meeting, business must be (a) pursuant to the
corporation's notice of meeting (or any supplement thereto), (b) by or at the
direction of the board of directors or (c) by any stockholder of the corporation
who is a stockholder of record at the time of giving of the notice provided for
in this Section 2.6, who shall be entitled to vote at such meeting and who
complies with the notice procedures set forth in this Section 2.6.

     Business to be brought before an annual meeting by a stockholder shall not
be considered properly brought if the stockholder has not given timely notice
thereof in writing to the secretary of the corporation. To be timely, a
stockholder's notice must be delivered to or mailed and received at the
principal executive offices of the corporation not less than sixty (60) nor more
than ninety (90) days prior to the first anniversary of the preceding year's
annual meeting; provided, however, that in the event that the date of the
meeting is changed by more than thirty (30) days from such anniversary date,
notice by the stockholder to be timely must be so received not later than the
close of business on the tenth (10th) day following the earlier of the day on
which such notice of the date of the meeting was mailed or such public
disclosure was made. A stockholder's notice to the secretary shall set forth as
to each matter the stockholder proposes to bring before the meeting: (i) a brief
description of the business desired to be brought before the meeting and the
reasons for conducting such business at the meeting, (ii) the name and address,
as they appear on the corporation's books, of the stockholder proposing such
business, and the name and address of the beneficial owner, if any, on whose
behalf the proposal is made, (iii) the class and number of shares of the
corporation, which are owned by the stockholder of record and by the beneficial
owner, if any, on whose behalf the proposal is made, (iv) any material interest
of the stockholder of record and the beneficial owner, if any, on whose behalf
the proposal is made in such business, and (v) any other information that is
required by law to be provided by the stockholder in his or her capacity as a
proponent of a stockholder proposal.

     Notwithstanding anything in these bylaws to the contrary, no business shall
be conducted at an annual meeting except in accordance with the procedures set
forth in this Section 2.6. The chairman of the meeting shall, if the facts
warrant, determine and declare to the meeting that a nomination was not made in
accordance with the procedures prescribed by the bylaws, and, if he or she
should so determine, he or she shall so declare to the meeting and the defective
nomination shall be disregarded. Notwithstanding the

                                       4
<PAGE>

foregoing provisions of this Bylaw, a stockholder shall also comply with all
applicable requirements of the Securities Exchange Act of 1934, as amended, and
the rules and regulations thereunder with respect to the matters set forth in
this Bylaw.

2.7  Manner of Giving Notice; Affidavit of Notice.
     --------------------------------------------

     Written notice of any meeting of stockholders, if mailed, is given when
deposited in the United States mail, postage prepaid, directed to the
stockholder at his address as it appears on the records of the corporation. An
affidavit of the secretary or an assistant secretary or of the transfer agent of
the corporation that the notice has been given shall, in the absence of fraud,
be prima facie evidence of the facts stated therein. If mailed, such notice
shall be deemed to be given when deposited in the mail, postage prepaid,
directed to the stockholder at his address as it appears on the records of the
corporation.

2.8  Quorum.
     ------

     The holders of a majority of the stock issued and outstanding and entitled
to vote thereat, present in person or represented by proxy, shall constitute a
quorum at all meetings of the stockholders for the transaction of business
except as otherwise provided by statute or by the certificate of incorporation.
If, however, such quorum is not present or represented at any meeting of the
stockholders, then either (a) the chairman of the meeting or (b) the
stockholders entitled to vote thereat, present in person or represented by
proxy, shall have power to adjourn the meeting from time to time, without notice
other than announcement at the meeting, until a quorum is present or
represented. At such adjourned meeting at which a quorum is present or
represented, any business may be transacted that might have been transacted at
the meeting as originally noticed.

2.9  Adjourned Meeting; Notice.
     -------------------------

     When a meeting is adjourned to another time or place, unless these bylaws
otherwise require, notice need not be given of the adjourned meeting if the time
and place thereof are announced at the meeting at which the adjournment is
taken. At the adjourned meeting the corporation may transact any business that
might have been transacted at the original meeting. If the adjournment is for
more than thirty (30) days, or if after the adjournment a new record date is
fixed for the adjourned meeting, a notice of the adjourned meeting shall be
given to each stockholder of record entitled to vote at the meeting.

2.10 Conduct of Business.
     -------------------

     The chairman of any meeting of stockholders shall determine the order of
business and the procedure at the meeting, including such regulation of the
manner of voting and the conduct of business.

                                       5
<PAGE>

2.11 Voting.
     ------

     The stockholders entitled to vote at any meeting of stockholders shall be
determined in accordance with the provisions of Section 2.14 of these bylaws,
subject to the provisions of Sections 217 and 218 of the General Corporation Law
of Delaware (relating to voting rights of fiduciaries, pledgors and joint owners
of stock and to voting trusts and other voting agreements).

     Except as provided in the certificate of incorporation, each stockholder
shall be entitled to one vote for each share of capital stock held by such
stockholder.

2.12 Waiver of Notice.
     ----------------

     Whenever notice is required to be given under any provision of the General
Corporation Law of Delaware or of the certificate of incorporation or these
bylaws, a written waiver thereof, signed by the person entitled to notice,
whether before or after the time stated therein, shall be deemed equivalent to
notice. Attendance of a person at a meeting shall constitute a waiver of notice
of such meeting, except when the person attends a meeting for the express
purpose of objecting, at the beginning of the meeting, to the transaction of any
business because the meeting is not lawfully called or convened. Neither the
business to be transacted at, nor the purpose of, any regular or special meeting
of the stockholders need be specified in any written waiver of notice unless so
required by the certificate of incorporation or these bylaws.

2.13 No Stockholder Action by Written Consent Without a Meeting Following
     ---------------------------------------------------------------------
     Initial Public Offering.
     -----------------------

     Any action required to be taken at any annual or special meeting of
stockholders of the corporation, or any action that may be taken at any annual
or special meeting of such stockholders, must be taken at an annual or special
meeting of stockholders of the corporation, with prior notice and with a vote,
and may not be taken by a consent in writing.

2.14 Record Date for Stockholder Notice; Voting.
     ------------------------------------------

     In order that the corporation may determine the stockholders entitled to
notice of or to vote at any meeting of stockholders or any adjournment thereof,
or entitled to receive payment of any dividend or other distribution or
allotment of any rights, or entitled to exercise any rights in respect of any
change, conversion or exchange of stock or for the purpose of any other lawful
action, the board of directors may fix, in advance, a record date, which shall
not be more than sixty (60) nor less than ten (10) days before the date of such
meeting, nor more than sixty (60) days prior to any other action.

     If the board of directors does not so fix a record date:

                                       6
<PAGE>

          (i)  The record date for determining stockholders entitled to notice
of or to vote at a meeting of stockholders shall be at the close of business on
the day next preceding the day on which notice is given, or, if notice is
waived, at the close of business on the day next preceding the day on which the
meeting is held.

          (ii) The record date for determining stockholders for any other
purpose shall be at the close of business on the day on which the board of
directors adopts the resolution relating thereto.

     A determination of stockholders of record entitled to notice of or to vote
at a meeting of stockholders shall apply to any adjournment of the meeting;
provided, however, that the board of directors may fix a new record date for the
adjourned meeting.

2.15 Proxies.
     -------

     Each stockholder entitled to vote at a meeting of stockholders may
authorize another person or persons to act for him by a written proxy, signed by
the stockholder and filed with the secretary of the corporation, but no such
proxy shall be voted or acted upon after three (3) years from its date, unless
the proxy provides for a longer period. A proxy shall be deemed signed if the
stockholder's name is placed on the proxy (whether by manual signature,
typewriting, telegraphic transmission or otherwise) by the stockholder or the
stockholder's attorney-in-fact. The revocability of a proxy that states on its
face that it is irrevocable shall be governed by the provisions of Section
212(c) of the General Corporation Law of Delaware.

                                  ARTICLE III

                                   DIRECTORS
                                   ---------

3.1  Powers.
     ------

     Subject to the provisions of the General Corporation Law of Delaware and
any limitations in the certificate of incorporation or these bylaws relating to
action required to be approved by the stockholders or by the outstanding shares,
the business and affairs of the corporation shall be managed and all corporate
powers shall be exercised by or under the direction of the board of directors.

3.2  Number of Directors.
     -------------------

     The authorized number of directors shall consist of nine (9) persons until
changed by a proper amendment of this Section 3.2.

     No reduction of the authorized number of directors shall have the effect of
removing any director before that director's term of office expires.

                                       7
<PAGE>

3.3  Election, Qualification and Term of Office of Directors.
     -------------------------------------------------------

     The board of directors shall be divided into three classes, as nearly equal
in number as possible with the term of office of the first class to expire at
the 2000 annual meeting of stockholders or any special meeting in lieu thereof,
the term of office of the second class to expire at the 2001 annual meeting of
stockholders or any special meeting in lieu thereof and the term of office of
the third class to expire at the 2002 annual meeting of stockholders or any
special meeting in lieu thereof. At each annual meeting of stockholders or
special meeting in lieu thereof following such initial classification, directors
elected to succeed those directors whose terms expire shall be elected for a
term of office to expire at the third succeeding annual meeting of the
stockholders or special meeting in lieu thereof after their election and until
their successors are duly elected and qualified. The foregoing provisions shall
become effective only when the corporation becomes a listed corporation within
the meaning of Section 301.5 of the California Corporations Code. Directors need
not be stockholders unless so required by the certificate of incorporation or
these bylaws, wherein other qualifications for directors may be prescribed.

     Subject to the rights of the holders of any series of Preferred Stock then
outstanding, newly created directorships resulting from any increase in the
authorized number of directors or any vacancies in the board of directors
resulting from death, resignation, retirement, disqualification, removal from
office or other cause may be filled only by a majority vote of the directors
then in office even though less than a quorum, or by a sole remaining director.
In the event of any increase or decrease in the authorized number of directors,
(a) each director then serving as such shall nevertheless continue as a director
of the class of which he or she is a member until the expiration of his or her
current term or his or her prior death, retirement, removal or resignation and
(b) the newly created or eliminated directorships resulting from such increase
or decrease shall if reasonably possible be apportioned by the board of
directors among the three classes of directors so as to ensure that no one class
has more than one director more than any other class. To the extent reasonably
possible, consistent with the foregoing rule, any newly created directorships
shall be added to those classes whose terms of office are to expire at the
latest dates following such allocation and newly eliminated directorships shall
be subtracted from those classes whose terms of office are to expire at the
earliest dates following such allocation, unless otherwise provided for from
time to time by resolution adopted by a majority of the directors then in
office, although less than a quorum. In the event of a vacancy in the board of
directors, the remaining directors, except as otherwise provided by law, may
exercise the powers of the full board of directors until the vacancy is filled.
Notwithstanding the foregoing, each director shall serve until his or her
successor is duly elected and qualified or until his or her death, resignation
or removal. No decrease in the number of directors constituting the board of
directors shall shorten the term of any incumbent director.

     Elections of directors need not be by written ballot.

                                       8
<PAGE>

     There shall be no right with respect to shares of stock of the corporation
to cumulate votes in the election of directors.

3.4  Place of Meetings; Meetings by Telephone.
     ----------------------------------------

     The board of directors of the corporation may hold meetings, both regular
and special, either within or outside the State of Delaware.

     Unless otherwise restricted by the certificate of incorporation or these
bylaws, members of the board of directors, or any committee designated by the
board of directors, may participate in a meeting of the board of directors, or
any committee, by means of conference telephone or similar communications
equipment by means of which all persons participating in the meeting can hear
each other, and such participation in a meeting shall constitute presence in
person at the meeting.

3.5  Regular Meetings.
     ----------------

     Regular meetings of the board of directors may be held without notice at
such time and at such place as shall from time to time be determined by the
board.

3.6  Special Meetings; Notice.
     ------------------------

     Special meetings of the board for any purpose or purposes may be called at
any time by the chairman of the board, the president, any vice president, the
secretary or any two (2) directors.

     Notice of the time and place of special meetings shall be delivered
personally or by telephone to each director or sent by first-class mail or
telegram, charges prepaid, addressed to each director at that director's address
as it is shown on the records of the corporation. If the notice is mailed, it
shall be deposited in the United States mail at lest four (4) days before the
time of the holding of the meeting. If the notice is delivered personally or by
telephone or by telegram, it shall be delivered personally or by telephone or to
the telegraph company at least forty-eight (48) hours before the time of the
holding of the meeting. Any oral notice given personally or by telephone may be
communicated either to the director or to a person at the office of the director
who the person giving the notice has reason to believe will promptly communicate
it to the director. The notice need not specify the purpose or the place of the
meeting, if the meeting is to be held at the principal executive office of the
corporation.

3.7  Quorum.
     ------

     At all meetings of the board of directors, a majority of the authorized
number of directors shall constitute a quorum for the transaction of business
and the act of a majority of the directors present at any meeting at which there
is a quorum shall be the act of the board of directors, except as may be
otherwise specifically provided by statute

                                       9
<PAGE>

or by the certificate of incorporation. If a quorum is not present at any
meeting of the board of directors, then the directors present thereat may
adjourn the meeting from time to time, without notice other than announcement at
the meeting, until a quorum is present.

     A meeting at which a quorum is initially present may continue to transact
business notwithstanding the withdrawal of directors, if any action taken is
approved by at least a majority of the required quorum for that meeting.

3.8  Waiver of Notice.
     ----------------

     Whenever notice is required to be given under any provision of the General
Corporation Law of Delaware or of the certificate of incorporation or these
bylaws, a written waiver thereof, signed by the person entitled to notice,
whether before or after the time stated therein, shall be deemed equivalent to
notice. Attendance of a person at a meeting shall constitute a waiver of notice
of such meeting, except when the person attends a meeting for the express
purpose of objecting, at the beginning of the meeting, to the transaction of any
business because the meeting is not lawfully called or convened. Neither the
business to be transacted at, nor the purpose of, any regular or special meeting
of the directors, or members of a committee of directors, need be specified in
any written waiver of notice unless so required by the certificate of
incorporation or these bylaws. If a quorum is not present at any meeting of the
board of directors, then the directors present thereat may adjourn the meeting
from time to time, without notice other than announcement at the meeting, until
a quorum is present.

3.9  Board Action by Written Consent Without a Meeting.
     -------------------------------------------------

     Unless otherwise restricted by the certificate of incorporation or these
bylaws, any action required or permitted to be taken at any meeting of the board
of directors, or of any committee thereof, may be taken without a meeting if all
members of the board or committee, as the case may be, consent thereto in
writing and the writing or writings are filed with the minutes of proceedings of
the board or committee. Written consents representing actions taken by the board
or committee may be executed by telex, telecopy or other facsimile transmission,
and such facsimile shall be valid and binding to the same extent as if it were
an original.

3.10 Fees and Compensation of Directors.
     ----------------------------------

     Unless otherwise restricted by the certificate of incorporation or these
bylaws, the board of directors shall have the authority to fix the compensation
of directors. No such compensation shall preclude any director from serving the
corporation in any other capacity and receiving compensation therefor.

                                       10
<PAGE>

3.11 Approval of Loans to Officers.
     -----------------------------

     The corporation may lend money to, or guarantee any obligation of, or
otherwise assist any officer or other employee of the corporation or of its
subsidiary, including any officer or employee who is a director of the
corporation or its subsidiary, whenever, in the judgment of the directors, such
loan, guaranty or assistance may reasonably be expected to benefit the
corporation. The loan, guaranty or other assistance may be with or without
interest and may be unsecured, or secured in such manner as the board of
directors shall approve, including, without limitation, a pledge of shares of
stock of the corporation. Nothing in this section contained shall be deemed to
deny, limit or restrict the powers of guaranty or warranty of the corporation at
common law or under any statute.

3.12 Removal of Directors.
     --------------------

     The holders of a majority of the shares then entitled to vote at an
election of directors may remove, only with cause, a director or directors of
the corporation.

     No reduction in the authorized number of directors shall have the effect of
removing any director prior to the expiration of such director's term of office.

3.13 Chairman of the Board of Directors.
     ----------------------------------

     The corporation may also have, at the discretion of the board of directors,
a chairman of the board of directors who shall not be considered an officer of
the corporation.

                                   ARTICLE IV

                                   COMMITTEES
                                   ----------

4.1  Committees of Directors.
     -----------------------

     The board of directors may, by resolution passed by a majority of the whole
board, designate one or more committees, with each committee to consist of one
or more of the directors of the corporation. The board may designate one or more
directors as alternate members of any committee, who may replace any absent or
disqualified member at any meeting of the committee. In the absence or
disqualification of a member of a committee, the member or members thereof
present at any meeting and not disqualified from voting, whether or not he or
they constitute a quorum, may unanimously appoint another member of the board of
directors to act at the meeting in the place of any such absent or disqualified
member. Any such committee, to the extent provided in the resolution of the
board of directors or in the bylaws of the corporation, shall have and may
exercise all the powers and authority of the board of directors in the
management of the business and affairs of the corporation, and may authorize the
seal of the corporation to be affixed to all papers that may require it; but no
such committee shall have the power

                                       11
<PAGE>

or authority to (i) amend the certificate of incorporation (except that a
committee may, to the extent authorized in the resolution or resolutions
providing for the issuance of shares of stock adopted by the board of directors
as provided in Section 151(a) of the General Corporation Law of Delaware, fix
the designations and any of the preferences or rights of such shares relating to
dividends, redemption, dissolution, any distribution of assets of the
corporation or the conversion into, or the exchange of such shares for, shares
of any other class or classes or any other series of the same or any other class
or classes of stock of the corporation), (ii) adopt an agreement of merger or
consolidation under Sections 251 or 252 of the General Corporation Law of
Delaware, (iii) recommend to the stockholders the sale, lease or exchange of all
or substantially all of the corporation's property and assets, (iv) recommend to
the stockholders a dissolution of the corporation or a revocation of a
dissolution, or (v) amend the bylaws of the corporation; and, unless the board
resolution establishing the committee, the bylaws or the certificate of
incorporation expressly so provide, no such committee shall have the power or
authority to declare a dividend, to authorize the issuance of stock, or to adopt
a certificate of ownership and merger pursuant to Section 253 of the General
Corporation Law of Delaware.

4.2  Committee Minutes.
     -----------------

     Each committee shall keep regular minutes of its meetings and report the
same to the board of directors when required.

4.3  Meetings and Action of Committees.
     ---------------------------------

     Meetings and actions of committees shall be governed by, and held and taken
in accordance with, the provisions of Article III of these bylaws, Section 3.4
(place of meetings and meetings by telephone), Section 3.5 (regular meetings),
Section 3.6 (special meetings and notice), Section 3.7 (quorum), Section 3.8
(waiver of notice) and Section 3.10 (action without a meeting), with such
changes in the context of those bylaws as are necessary to substitute the
committee and its members for the board of directors and its members; provided,
however, that the time of regular meetings of committees may also be called by
resolution of the board of directors and that notice of special meetings of
committees shall also be given to all alternate members, who shall have the
right to attend all meetings of the committee. The board of directors may adopt
rules for the government of any committee not inconsistent with the provisions
of these bylaws.

                                   ARTICLE V

                                   OFFICERS
                                   --------

5.1  Officers.
     --------

     The officers of the corporation shall be a chief executive officer, a
president, a secretary, and a chief financial officer. The corporation may also
have, at the discretion

                                       12
<PAGE>

of the board of directors, one or more vice presidents, one or more assistant
secretaries, one or more assistant treasurers, and any such other officers as
may be appointed in accordance with the provisions of Section 5.3 of these
bylaws. Any number of offices may be held by the same person.

5.2  Appointment of Officers.
     -----------------------

     The officers of the corporation, except such officers as may be appointed
in accordance with the provisions of Sections 5.3 or 5.5 of these bylaws, shall
be chosen by the board of directors, subject to the rights, if any, of an
officer under any contract of employment.

5.3  Subordinate Officers.
     --------------------

     The board of directors may appoint, or empower the chief executive officer
or the president to appoint, such other officers and agents as the business of
the corporation may require, each of whom shall hold office for such period,
have such authority, and perform such duties as are provided in these bylaws or
as the board of directors may from time to time determine.

5.4  Removal and Resignation of Officers.
     -----------------------------------

     Subject to the rights, if any, of an officer under any contract of
employment, any officer may be removed, either with or without cause, by an
affirmative vote of the majority of the board of directors at any regular or
special meeting of the board or, except in the case of an officer chosen by the
board of directors, by any officer upon whom such power of removal may be
conferred by the board of directors.

     Any officer may resign at any time by giving written notice to the
corporation.  Any resignation shall take effect at the date of the receipt of
that notice or at any later time specified in that notice; and, unless otherwise
specified in that notice, the acceptance of the resignation shall not be
necessary to make it effective. Any resignation is without prejudice to the
rights, if any, of the corporation under any contract to which the officer is a
party.

5.5  Vacancies in Offices.
     --------------------

     Any vacancy occurring in any office of the corporation shall be filled by
the board of directors.

5.6  Chief Executive Officer.
     -----------------------

     Subject to such supervisory powers, if any, as may be given by the board of
directors to the chairman of the board, the chief executive officer of the
corporation shall, subject to the control of the board of directors, have
general supervision, direction and

                                       13
<PAGE>

control of the business and officers of the corporation. The chief executive
officer shall preside at all meetings of the stockholders and, in the absence or
nonexistence of a chairman of the board, at all meetings of the board of
directors. The chief executive officer shall have the general powers and duties
of management usually vested in the office of chief executive officer of a
corporation and shall have such other powers and duties as may be prescribed by
the board of directors or these bylaws.

5.7  President.
     ---------

     Subject to such supervisory powers, if any, as may be given by the board of
directors to the chairman of the board or the chief executive officer, the
president of the corporation shall have general supervision, direction and
control of the business and officers of the corporation. The president shall
have the general powers and duties of management usually vested in the office of
president of a corporation and shall have such other powers and duties as may be
prescribed by the board of directors or these bylaws.

5.8  Vice Presidents.
     ---------------

     In the absence or disability of the chief executive officer and president,
the vice presidents, if any, in order of their rank as fixed by the board of
directors or, if not ranked, a vice president designated by the board of
directors, shall perform all the duties of the president and when so acting
shall have all the powers of, and be subject to all the restrictions upon, the
president. The vice presidents shall have such other powers and perform such
other duties as from time to time may be prescribed for them respectively by the
board of directors, these bylaws, the president or the chairman of the board.

5.9  Secretary.
     ---------

     The secretary shall keep or cause to be kept, at the principal executive
office of the corporation or at such other place as the board of directors may
direct, a book of minutes of all meetings and actions of directors, committees
of directors, and stockholders. The minutes shall show the time and place of
each meeting, the names of those present at directors' meetings or committee
meetings, the number of shares present or represented at stockholders' meetings,
and the proceedings thereof.

     The secretary shall keep, or cause to be kept, at the principal executive
office of the corporation or at the office of the corporation's transfer agent
or registrar, as determined by resolution of the board of directors, a share
register, or a duplicate share register, showing the names of all stockholders
and their addresses, the number and classes of shares held by each, the number
and date of certificates evidencing such shares, and the number and date of
cancellation of every certificate surrendered for cancellation.

     The secretary shall give, or cause to be given, notice of all meetings of
the stockholders and of the board of directors required to be given by law or by
these bylaws.  The secretary shall keep the seal of the corporation, if one be
adopted, in safe custody and

                                       14
<PAGE>

shall have such other powers and perform such other duties as may be prescribed
by the board of directors or by these bylaws.

5.10  Chief Financial Officer.
      -----------------------

      The chief financial officer shall keep and maintain, or cause to be kept
and maintained, adequate and correct books and records of accounts of the
properties and business transactions of the corporation, including accounts of
its assets, liabilities, receipts, disbursements, gains, losses, capital
retained earnings, and shares.  The books of account shall at all reasonable
times be open to inspection by any director.

      The chief financial officer shall deposit all moneys and other valuables
in the name and to the credit of the corporation with such depositories as may
be designated by the board of directors. The chief financial officer shall
disburse the funds of the corporation as may be ordered by the board of
directors, shall render to the president and directors, whenever they request
it, an account of all his or her transactions as chief financial officer and of
the financial condition of the corporation, and shall have other powers and
perform such other duties as may be prescribed by the board of directors or by
the bylaws.

5.11  Representation of Shares of Other Corporations.
      ----------------------------------------------

      The chairman of the board, the chief executive officer, the president, any
vice president, the chief financial officer, the secretary or any assistant
secretary of this corporation, or any other person authorized by the board of
directors or the chief executive officer or the president or a vice president,
is authorized to vote, represent, and exercise on behalf of this corporation all
rights incident to any and all shares of any other corporation or corporations
standing in the name of this corporation.  The authority granted herein may be
exercised either by such person directly or by any other person authorized to do
so by proxy or power of attorney duly executed by such person having the
authority.

5.12  Authority and Duties of Officers.
      --------------------------------

      In addition to the foregoing authority and duties, all officers of the
corporation shall respectively have such authority and perform such duties in
the management of the business of the corporation as may be designated from time
to time by the board of directors or the stockholders.

                                       15
<PAGE>

                                  ARTICLE VI

                    INDEMNIFICATION OF DIRECTORS, OFFICERS,
                    ---------------------------------------
                          EMPLOYEES AND OTHER AGENTS
                          --------------------------

6.1  Indemnification of Directors and Officers.
     -----------------------------------------

     The corporation shall, to the maximum extent and in the manner permitted by
the General Corporation Law of Delaware, indemnify each of its directors and
officers against expenses (including attorneys' fees), judgments, fines,
settlements, and other amounts actually and reasonably incurred in connection
with any proceeding, arising by reason of the fact that such person is or was an
agent of the corporation. For purposes of this Section 6.1, a "director" or
"officer" of the corporation includes any person (i) who is or was a director or
officer of the corporation, (ii) who is or was serving at the request of the
corporation as a director or officer of another corporation, partnership, joint
venture, trust or other enterprise, or (iii) who was a director or officer of a
corporation which was a predecessor corporation of the corporation or of another
enterprise at the request of such predecessor corporation.

6.2  Indemnification of Others.
     -------------------------

     The corporation shall have the power, to the extent and in the manner
permitted by the General Corporation Law of Delaware, to indemnify each of its
employees and agents (other than directors and officers) against expenses
(including attorneys' fees), judgments, fines, settlements, and other amounts
actually and reasonably incurred in connection with any proceeding, arising by
reason of the fact that such person is or was an agent of the corporation.  For
purposes of this Section 6.2, an "employee" or "agent" of the corporation (other
than a director or officer) includes any person (i) who is or was an employee or
agent of the corporation, (ii) who is or was serving at the request of the
corporation as an employee or agent of another corporation, partnership, joint
venture, trust or other enterprise, or (iii) who was an employee or agent of a
corporation which was a predecessor corporation of the corporation or of another
enterprise at the request of such predecessor corporation.

6.3  Payment of Expenses in Advance.
     ------------------------------

     Expenses incurred in defending any action or proceeding for which
indemnification is required pursuant to Section 6.1 or for which indemnification
is permitted pursuant to Section 6.2 following authorization thereof by the
board of directors shall be paid by the corporation in advance of the final
disposition of such action or proceeding upon receipt of an undertaking by or on
behalf of the indemnified party to repay such amount if it shall ultimately be
determined that the indemnified party is not entitled to be indemnified as
authorized in this Article 6.

                                       16
<PAGE>

6.4  Indemnity Not Exclusive.
     -----------------------

     The indemnification provided by this Article 6 shall not be deemed
exclusive of any other rights which those seeking indemnification may be
entitled under any bylaw, agreement, vote of shareholders or disinterested
directors or otherwise, both as to action in an official capacity and as to
action in another capacity while holding such office, to the extent that
additional rights to indemnification are authorized in the certificate of
incorporation.

6.5  Insurance.
     ---------

     The corporation may purchase and maintain insurance on behalf of any person
who is or was a director, officer, employee or agent of the corporation, or is
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 liability asserted against him and incurred by him
in any such capacity, or arising out of his status as such, whether or not the
corporation would have the power to indemnify him against such liability under
the provisions of the General Corporation Law of Delaware.

6.6  Conflicts.
     ---------

     No indemnification or advance shall be made under this Article 6, except
where such indemnification or advance is mandated by law or the order, judgment
or decree of any court of competent jurisdiction, in any circumstance where it
appears:

          (i)  That it would be inconsistent with a provision of the certificate
of incorporation, these bylaws, a resolution of the stockholders or an agreement
in effect at the time of the accrual of the alleged cause of the action asserted
in the proceeding in which the expenses were incurred or other amounts were
paid, which prohibits or otherwise limited indemnification; or

          (ii) That it would be inconsistent with any condition expressly
imposed by a court in approving a settlement.

                                  ARTICLE VII

                              RECORDS AND REPORTS
                              -------------------

7.1  Maintenance and Inspection of Records.
     -------------------------------------

     The corporation shall, either at its principal executive office or at such
place or places as designated by the board of directors, keep a record of its
shareholders listing their names and addresses and the number and class of
shares held by each shareholder, a copy of these bylaws as amended to date,
accounting books, and other records.

                                       17
<PAGE>

     Any stockholder of record, in person or by attorney or other agent, shall,
upon written demand under oath stating the purpose thereof, have the right
during the usual hours for business to inspect for any proper purpose the
corporation's stock ledger, a list of its stockholders, and its other books and
records and to make copies or extracts therefrom. A proper purpose shall mean a
purpose reasonably related to such person's interest as a stockholder. In every
instance where an attorney or other agent is the person who seeks the right to
inspection, the demand under oath shall be accompanied by a power of attorney or
such other writing that authorizes the attorney or other agent to so act on
behalf of the stockholder. The demand under oath shall be directed to the
corporation at its registered office in Delaware or at its principal place of
business.

7.2  Inspection by Directors.
     -----------------------

     Any director shall have the right to examine the corporation's stock
ledger, a list of its stockholders, and its other books and records for a
purpose reasonably related to his position as a director. The Court of Chancery
is hereby vested with the exclusive jurisdiction to determine whether a director
is entitled to the inspection sought. The Court may summarily order the
corporation to permit the director to inspect any and all books and records, the
stock ledger, and the stock list and to make copies or extracts therefrom. The
Court may, in its discretion, prescribe any limitations or conditions with
reference to the inspection, or award such other and further relief as the Court
may deem just and proper.

7.3  Annual Statement to Stockholders.
     --------------------------------

     The board of directors shall present at each annual meeting, and at any
special meeting of the stockholders when called for by the vote of the
stockholders, a full and clear statement of the business and condition of the
corporation.

                                  ARTICLE VII

                                GENERAL MATTERS
                                ---------------

8.1  Checks.
     ------

     From time to time, the board of directors shall determine by resolution
which person or persons may sign or endorse all checks, drafts, other orders for
payment of money, notes or other evidences of indebtedness that are issued in
the name of or payable to the corporation, and only the persons so authorized
shall sign or endorse those instruments.

8.2  Execution of Corporate Contracts and Instruments.
     ------------------------------------------------

     The board of directors, except as otherwise provided in these bylaws, may
authorize any officer or officers, or agent or agents, to enter into any
contract or execute

                                       18
<PAGE>

any instrument in the name of and on behalf of the corporation; such authority
may be general or confined to specific instances. Unless so authorized or
ratified by the board of directors or within the agency power of an officer, no
officer, agent or employee shall have any power or authority to bind the
corporation by any contract or engagement or to pledge its credit or to render
it liable for any purpose or for any amount.

8.3  Stock Certificates; Partly Paid Shares.
     --------------------------------------

     The shares of a corporation shall be represented by certificates, provided
that the board of directors of the corporation may provide by resolution or
resolutions that some or all of any or all classes or series of its stock shall
be uncertificated shares. Any such resolution shall not apply to shares
represented by a certificate until such certificate is surrendered to the
corporation. Notwithstanding the adoption of such a resolution by the board of
directors, every holder of stock represented by certificates and upon request
every holder of uncertificated shares shall be entitled to have a certificate
signed by, or in the name of the corporation by the chairman or vice-chairman of
the board of directors, or the chief executive officer or the president or vice-
president, and by the chief financial officer or an assistant treasurer, or the
secretary or an assistant secretary of such corporation representing the number
of shares registered in certificate form. Any or all of the signatures on the
certificate may be a facsimile. In case any officer, transfer agent or registrar
who has signed or whose facsimile signature has been placed upon a certificate
has ceased to be such officer, transfer agent or registrar before such
certificate is issued, it may be issued by the corporation with the same effect
as if he were such officer, transfer agent or registrar at the date of issue.

     The corporation may issue the whole or any part of its shares as partly
paid and subject to call for the remainder of the consideration to be paid
therefor. Upon the face or back of each stock certificate issued to represent
any such partly paid shares, upon the books and records of the corporation in
the case of uncertificated partly paid shares, the total amount of the
consideration to be paid therefor and the amount paid thereon shall be stated.
Upon the declaration of any dividend on fully paid shares, the corporation shall
declare a dividend upon partly paid shares of the same class, but only upon the
basis of the percentage of the consideration actually paid thereon.

8.4  Special Designation on Certificates.
     -----------------------------------

     If the corporation is authorized to issue more than one class of stock or
more than one series of any class, then the powers, the designations, the
preferences, and the relative, participating, optional or other special rights
of each class of stock or series thereof and the qualifications, limitations or
restrictions of such preferences and/or rights shall be set forth in full or
summarized on the face or back of the certificate that the corporation shall
issue to represent such class or series of stock; provided, however, that,
except as otherwise provided in Section 202 of the General Corporation Law of
Delaware, in lieu of the foregoing requirements there may be set forth on the
face or back of the certificate that the corporation shall issue to represent
such class or series of stock a

                                       19
<PAGE>

statement that the corporation will furnish without charge to each stockholder
who so requests the powers, the designations, the preferences, and the relative,
participating, optional or other special rights of each class of stock or series
thereof and the qualifications, limitations or restrictions of such preferences
and/or rights.

8.5  Lost Certificates.
     -----------------

     Except as provided in this Section 8.5, no new certificates for shares
shall be issued to replace a previously issued certificate unless the latter is
surrendered to the corporation and canceled at the same time. The corporation
may issue a new certificate of stock or uncertificated shares in the place of
any certificate theretofore issued by it, alleged to have been lost, stolen or
destroyed, and the corporation may require the owner of the lost, stolen or
destroyed certificate, or his legal representative, to give the corporation a
bond sufficient to indemnify it against any claim that may be made against it on
account of the alleged loss, theft or destruction of any such certificate or the
issuance of such new certificate or uncertificated shares.

8.6  Construction; Definitions.
     -------------------------

     Unless the context requires otherwise, the general provisions, rules of
construction, and definitions in the Delaware General Corporation Law shall
govern the construction of these bylaws. Without limiting the generality of this
provision, the singular number includes the plural, the plural number includes
the singular, and the term "person" includes both a corporation and a natural
person.

8.7  Dividends.
     ---------

     The directors of the corporation, subject to any restrictions contained in
the certificate of incorporation, may declare and pay dividends upon the shares
of its capital stock pursuant to the General Corporation Law of Delaware.
Dividends may be paid in cash, in property, or in shares of the corporation's
capital stock.

     The directors of the corporation may set apart out of any of the funds of
the corporation available for dividends a reserve or reserves for any proper
purpose and may abolish any such reserve. Such purposes shall include but not be
limited to equalizing dividends, repairing or maintaining any property of the
corporation, and meeting contingencies.

8.8  Fiscal Year.
     -----------

     The fiscal year of the corporation shall be fixed by resolution of the
board of directors and may be changed by the board of directors.

                                       20
<PAGE>

8.9   Seal.
      ----

      The corporation may have a corporate seal, which shall be adopted and
which may be altered by the board of directors, and may use the same by causing
it or a facsimile thereof, to be impressed or affixed or in any other manner
reproduced.

8.10  Transfer of Stock.
      -----------------

      Upon surrender to the corporation or the transfer agent of the corporation
of a certificate for shares duly endorsed or accompanied by proper evidence of
succession, assignation or authority to transfer, it shall be the duty of the
corporation to issue a new certificate to the person entitled thereto, cancel
the old certificate, and record the transaction in its books.

8.11  Stock Transfer Agreements.
      -------------------------

     The corporation shall have power to enter into and perform any agreement
with any number of shareholders of any one or more classes of stock of the
corporation to restrict the transfer of shares of stock of the corporation of
any one or more classes owned by such stockholders in any manner not prohibited
by the General Corporation Law of Delaware.

8.12  Registered Stockholders.
      -----------------------

      The corporation shall be entitled to recognize the exclusive right of a
person registered on its books as the owner of shares to receive dividends and
to vote as such owner, shall be entitled to hold liable for calls and
assessments the person registered on its books as the owner of shares, and shall
not be bound to recognize any equitable or other claim to or interest in such
share or shares on the part of another person, whether or not it shall have
express or other notice thereof, except as otherwise provided by the laws of
Delaware.

                                  ARTICLE IX

                                  AMENDMENTS
                                  ----------

      The bylaws of the corporation may be adopted, amended or repealed by the
stockholders entitled to vote; provided, however, that the corporation may, in
its certificate of incorporation, confer the power to adopt, amend or repeal
bylaws upon the directors.  The fact that such power has been so conferred upon
the directors shall not divest the stockholders of the power, nor limit their
power to adopt, amend or repeal bylaws.

                                       21
<PAGE>

                          CERTIFICATE OF ADOPTION OF

                          AMENDED AND RESTATED BYLAWS

                                      OF

                     NORTHPOINT COMMUNICATIONS GROUP, INC.



     The undersigned hereby certifies that he is the duly elected, qualified,
and acting Secretary of NorthPoint Communications Group, Inc. (the
"Corporation") and that the foregoing Amended and Restated Bylaws, comprising
twenty-one (21) pages, were adopted as the Amended and Restated Bylaws of the
Corporation on January 19, 2000, by the Board of Directors of the Corporation at
a meeting on January 19, 2000.

     IN WITNESS WHEREOF, the undersigned has hereunto set his hand and affixed
the corporate seal this 19th day of January, 2000.


                                                    /s/ Steven J. Gorosh
                                                    ------------------------
                                                    Steven J. Gorosh,
                                                    Secretary