EXHIBIT 10.3
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                         SBA COMMUNICATIONS CORPORATION

                             SHAREHOLDERS AGREEMENT

         This Shareholders Agreement (this "Agreement") is made and entered into
as of  the  date  set  forth  below  by  and  among  Steven  E.  Bernstein,  SBA
Communications  Corporation,  a Florida  corporation  (the  "Company"),  and the
purchasers of shares of Series A Convertible Preferred Stock.

         WHEREAS, Mr. Bernstein holds an aggregate of 8,075,000 shares of the
Company's Class B Common Stock; and

         WHEREAS,  the Company is as of this date consummating the Closing under
a Series A Preferred Stock Purchase  Agreement (the "Stock Purchase  Agreement")
pursuant to which the Company is issuing to certain  purchasers shares of Series
A Convertible Preferred Stock, par value $.01 per share (the "Series A Preferred
Stock") and the Company is issuing to Alex. Brown & Sons  Incorporated a warrant
(the "Agent's  Warrant") to purchase shares of Class A Common Stock (each Person
(defined below), who acquires any such shares of Class A Common Stock or holds a
warrant to purchase  shares of Series A Preferred  Stock or the shares  acquired
upon the  exercise of such  warrant,  being  herein  referred to as a "Preferred
Shareholder" and collectively with Mr. Bernstein, the "Shareholders"); and

         WHEREAS,  the Stock  Purchase  Agreement  provides  that the  Preferred
Shareholders  shall become parties to this Agreement by executing and delivering
a signature page to this Agreement;

         NOW,  THEREFORE,  in  consideration of the foregoing and the agreements
set forth below, the parties hereby agree as follows:

         1.       CERTAIN DEFINED TERMS

                  As used in this Agreement,  the following terms shall have the
following respective meanings:

                  "Affiliate"  shall mean (a) any Person  directly or indirectly
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controlling,  controlled by or under common control with another Person; (b) any
Person owning or controlling ten percent (10%) or more of the outstanding voting
securities  of such other Person;  (c) any officer,  director or partner of such
Person; (d) any liquidating trust, trustee or other similar Person or entity for
any  Person;  or (e) in case of an  individual,  any family  member to whom such
individual may transfer his or her shares pursuant to Section 2 hereof.

                  "Charter" shall mean the Articles of Incorporation of the
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Company, as amended from time to time.

                  "Class B Common  Stock"  shall mean and include the  Company's
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Class B Common  Stock,  par value $.01 per share,  as  authorized on the date of
this  Agreement and any other  securities  into which or for which the Company's
Class  B  Common  Stock  is  converted  or  exchanged  pursuant  to  a  plan  of
reorganization,  recapitalization, merger, sale of assets, the provisions of the
Charter or otherwise.

                  "Common Stock  Conversion  Shares" shall mean (a) those shares
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of Class A Common  Stock, par value $.01 per share, of the Company issued or
issuable upon the conversion of the Series A 

 
Preferred Stock or Class B Common Stock, as adjusted from time to time and (b)
those shares of Class A Common Stock issuable upon the exercise of the Agent's
Warrant.

                  "Conversion  Price"  shall mean the price,  as in effect  from
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time to time, at which shares of Series A Preferred Stock are  convertible  into
Common Stock Conversion Shares as defined in, and pursuant to, the Charter.

                  "Eligible Class B Stockholder" shall mean members of Steven E.
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Bernstein's  Immediate  Family or their  lineal  descendants,  spouses of lineal
descendants  or lineal  descendants  of  spouses,  whether  alive as of the date
hereof or born  subsequently,  any trusts or other estate planning  vehicles for
the benefit of any of the foregoing,  whether  existing as of the date hereof or
created  subsequently.  "Immediate  Family" of Mr.  Bernstein  shall include his
spouse,  parents,  children,  siblings,  mother  and  father-in-law,   sons  and
daughters-in-laws and brothers and sisters-in-law.

                  "Person"   shall  mean  any   natural   person,   partnership,
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corporation or other legal entity.

                  "Qualified Public Offering" shall mean and include the closing
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of a firmly underwritten  public offering pursuant to an effective  registration
statement under the Securities Act of 1933, as amended (the  "Securities  Act"),
covering  the offer and sale of Common Stock for the account of the Company from
which the aggregate gross proceeds to the Company equal or exceed $20,000,000 at
a per share issue price of at least 150% of the then applicable Conversion Price
of Conversion Shares if such public offering occurs before June 30, 1998 or at a
price  share  of at least  200% of the  then  applicable  Conversion  Price  and
Conversion Shares if such public offering occurs on or after June 30, 1998.

                  "Shares" of a Shareholder shall mean and include all Stock now
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owned or hereafter acquired by such Shareholder.

                  "Stock"  shall mean and  include  all shares of Class B Common
                   -----
Stock,  Conversion Shares, or Series A Preferred Stock, and all other securities
of the  Company  that may be issued in  exchange  for or in respect of shares of
Class  B  Common  Stock,   Conversion  Shares,  or  Series  A  Preferred  Stock,
respectively  (whether  by way of  stock  split,  stock  dividend,  combination,
reclassification, reorganization or any other means).

         2.       PROHIBITED TRANSFERS

                  Mr. Bernstein  may  not  sell or  transfer  all or any of his
shares of Class B Common  Stock  except to an Eligible  Class B  Stockholder  or
except in accordance with this Agreement, and no attempted transfer of any Class
B  Common  Stock  in  violation  of any  provision  of this  Agreement  shall be
effective to pass any title or interest therein.

         3.       RIGHT OF PARTICIPATION IN SALES

                  (a) If at any time Mr.  Bernstein  desires to sell or transfer
all or any part of his shares of Class B Common Stock or Common Stock Conversion
Shares to a Person (a "Purchaser"),  Mr.  Bernstein (the "Selling  Shareholder")
shall promptly give written notice (the "Offer" for the purposes of this Section
3) to the Preferred  Shareholders.  The Offer shall disclose the identity of the
Purchaser,  the  

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number of shares of Class B Common Stock or Common Stock Conversion Shares to be
sold or transferred, the total number of shares of Class B Common Stock and
Common Stock Conversion Shares owned by the Selling Shareholder, the terms and
conditions, including price, (calculated in the case of shares of Class B Common
Stock by treating such shares as then converted to Common Stock Conversion
Shares) of the proposed sale, and any other material facts relating to the
proposed sale.

                  (b) Each Preferred Shareholder shall have the right to sell to
the Purchaser,  as a condition to such sale by such Selling Shareholder desiring
to sell, at the same price per share (calculated in the case of shares of Series
A Preferred  Stock by treating  such shares as then  converted  to Common  Stock
Conversion Shares and shares of the Company's Series B Preferred Stock, $.01 par
value,  per share (the  "Series B Preferred  Stock"))  and on the same terms and
conditions as involved in such sale by the Selling Shareholder,  all or any part
of that number of Common Stock  Conversion  Shares equal to the product obtained
by  multiplying  (i) the  aggregate  number of Common  Stock  Conversion  Shares
covered by the Offer by (ii) a fraction the  numerator of which is the number of
Common Stock Conversion Shares held by such Preferred Shareholder at the time of
the sale or transfer and the  denominator of which is the total number of Common
Stock Conversion Shares (calculated by treating such shares as then converted to
Common Stock Conversion  Shares) held at the time of the sale or transfer by the
Selling Shareholder and all the Preferred  Shareholders  exercising their rights
of  participation  hereunder (such Preferred  Shareholder  being herein called a
"Participating   Shareholder");   provided,   however,  that  any  Participating
Shareholder  shall not be  required  to  deliver to the  Purchaser  any Series B
Preferred  Stock or any other  property  other than the Common Stock  Conversion
Shares in connection with the proposed purchase by the Purchaser.

                  (c) If a Participating Shareholder wishes to so participate in
any  sale  under  this  Section  3,  he,  she or it  shall  notify  the  Selling
Shareholder  in  writing  of such  intention  as soon as  practicable  after the
Participating  Shareholder's  receipt of the Offer,  and in any event  within 30
days after the date the notice of the Offer was given. Such  notification  shall
be  delivered  to the Selling  Shareholder  (with  copies to the Company and the
Preferred Shareholders).

                  (d)  The   Selling   Shareholder   and   other   Participating
Shareholders shall sell to the Purchaser all, or at the option of the Purchaser,
any part of the Common Stock  Conversion  Shares  proposed to be sold by them at
not more than the price and upon other terms and  conditions,  if any,  not more
favorable to the Purchaser than those in the Offer; provided,  however, that any
purchase  of less than all of such  Shares by the  Purchaser  shall  require the
consent of each  Participating  Shareholder  and shall be made from the  Selling
Shareholder and the Participating  Shareholders pro rata based upon the relative
amount  of the  Shares  that  the  Selling  Shareholder  and  the  Participating
Shareholders are otherwise entitled to sell pursuant to Section 3(b) hereof.

                  (e) Each Participating Shareholder who is a holder of Series A
Preferred  Stock shall effect its  participation  in the sale by converting  its
Series A Preferred  Stock into Series B Preferred Stock and Class A Common Stock
and then  promptly  delivering  to the Selling  Shareholder  for transfer to the
prospective purchaser one or more certificates,  properly endorsed for transfer,
which  represent  the  number  of  shares  of Class A Common  Stock  which  such
Participating  Shareholder  elects to sell.  The Company agrees to make any such
conversion  concurrent with the actual transfer of such shares to the Purchaser.
The  Participating  Shareholders  shall be under no  obligation  to transfer any
shares of Series B Preferred  Stock received upon such conversion as a result of
the operation of this Section 3.

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                  (f)  The  rights   afforded   by  this   Section  3  shall  be
inapplicable  where Mr.  Bernstein  elects to transfer any or all of his Class B
Common Stock to an Eligible Class B Stockholder.

         4.       EXPIRATION OF AGREEMENT

                  Notwithstanding   Section  8  hereof  to  the  contrary,  this
Agreement shall expire and terminate on the  consummation of a Qualified  Public
Offering.

         5.       SPECIFIC ENFORCEMENT

                  Each  Shareholder  expressly agrees that he, she or it and the
Company  will be  irreparably  damaged  if this  Agreement  is not  specifically
enforced.  Upon a breach or  threatened  breach of the terms,  covenants  and/or
conditions of this Agreement by a Shareholder,  the other  Shareholders  and the
Company  shall,  in  addition  to all  other  remedies,  each be  entitled  to a
temporary or permanent  injunction,  without showing any actual damage, and/or a
decree for specific performance, in accordance with the provisions hereof.

         6.       LEGEND

                  Each  certificate  evidencing  any of the  shares  of  Class B
Common Stock shall bear a legend substantially as follows:

                  The shares  represented  by this  certificate  are  subject to
                  restrictions  on  transfer  and  may not be  sold,  exchanged,
                  transferred,  pledged,  hypothecated or otherwise  disposed of
                  except in  accordance  with and  subject  to all the terms and
                  conditions  of a certain  Shareholders  Agreement  dated as of
                  March 6, 1997,  as amended  from time to time, a copy of which
                  the  Company  will  furnish to the holder of this  certificate
                  upon request and without charge.

         7.       NOTICE

                  Any notice  required or permitted to be given  hereunder shall
be in writing and shall be deemed to be properly  given when sent by  registered
or certified mail, return receipt  requested,  by guaranteed  overnight delivery
service or by facsimile transmission, addressed as follows:

           If to the Company:        SBA Communications Corporation
                                     6001 Broken Sound Parkway
                                     Boca Raton, Florida  33487
                                     Attention: Steven E. Bernstein, President

           If to the Shareholders:   At their respective addresses set forth on
                                     their signature pages hereto;

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or, as to any of the foregoing, to such other address as any such party may give
the others  notice of  pursuant to this  Section 7,  provided,  however,  that a
change of address shall only be effective upon receipt.

         8.       BOARD OF DIRECTORS AND AUTHORITY OF THE BOARD

                  (a) The Board of Directors of the  Corporation  (the  "Board")
shall be comprised initially of five (5) directors.  The holders of the Series A
Preferred Stock shall be entitled to designate two (2) directors as follows: ABS
Capital Partners II, L.P. shall be entitled to designate one director and Advent
VII, L.P. shall be entitled to designate one director. Steven E. Bernstein shall
be entitled to designate two directors,  one of which may be himself.  The final
director shall be an  independent  director  designated by Mr.  Bernstein who is
reasonably acceptable to the directors designated by the holders of the Series A
Preferred  Stock.  In the  event of any  vacancy  on the Board  arising  for any
reason,  the  Shareholders or class of Shareholders  who designated the director
whose  office has become  vacant  shall be  entitled  to  designate  a successor
director.  If any  Shareholder  or  class of  Shareholders  notifies  the  other
stockholder(s)  in  writing  that he  wishes to  remove a  director  whom he has
designated,  the  other  stockholders  shall  cooperate  in  taking  all  action
necessary to effect the removal of such director as promptly as practicable.

                  (b) All  proposed  acquisitions  of  stock  or  assets  by the
Company or any of its subsidiaries with a purchase price in excess of $1,000,000
must be approved by the Board.

                  (c) The Board shall  establish  a  Compensation  Committee  of
three (3) members, consisting of the two (2) directors designated by the holders
of the Series A Preferred  Stock and one (1)  director  designated  by Steven E.
Bernstein, which may be himself.

                  (d)  Shareholders  shall vote all of their Stock,  execute and
deliver such  further  documents,  take such  further  action and use their best
efforts to cause their representatives on the Board to vote in such a manner, as
may be  necessary  or  desirable  to carry out the  purpose  and  intent of this
Section 8 and the other provisions of this Agreement.

                  (e) If a Shareholder  shall at any time fail or refuse to vote
his Stock as provided in  paragraphs  (b) through (d) above,  thereupon  without
further  action  by any  person,  such  Shareholders  shall  be  deemed  to have
irrevocably   appointed,   and  hereby  does  irrevocably   appoint,  the  other
stockholders  who are a party to this Agreement as his or her attorney and proxy
to vote his Stock as provided in this Section 8.

         9.       GOVERNING LAW; SUCCESSORS AND ASSIGNS

                  This  Agreement  shall be governed by the laws of the State of
Florida and except as expressly provided herein shall be binding upon the heirs,
personal representatives,  executors, administrators,  successors and assigns of
the parties. The rights of the Preferred  Shareholders  hereunder are assignable
to any  assignee  or  transferee  of all or a portion of the Shares held by such
Preferred Shareholders.

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         10.      RIGHTS AND OBLIGATIONS OF CERTAIN TRANSFEREES OF SHARES

                  If Mr. Bernstein transfers any of his shares of Class B Common
Stock to any  Eligible  Class B  Stockholder,  such  transferee  shall  agree in
writing, as a condition to such transfer,  that any future sales or transfers of
such shares of Class B Common  Stock by the holder  thereof  (the  "Transferring
Holder") shall be subject to the  restrictions on transfer set forth in Sections
2 and 3 hereof.

         11.      SEVERABILITY

                  If any  provision  of  this  Agreement  shall  be  held  to be
illegal,   invalid   or   unenforceable,    such   illegality,   invalidity   or
unenforceability shall attach only to such provision and shall not in any manner
affect or render illegal,  invalid or unenforceable  any other provision of this
Agreement,  and this  Agreement  shall be  carried  out as if any such  illegal,
invalid or unenforceable provision were not contained herein.

         12.      HEADINGS

                  Headings in this Agreement are included for reference only and
shall have no effect upon the construction or interpretation of any part of this
Agreement.

         13.      COUNTERPARTS

                  This  Agreement  may be executed in two or more  counterparts,
each of which  shall be  deemed an  original,  but all of which  together  shall
constitute one and the same instrument.

         14.      REPORTING REQUIREMENTS

                  The Company  will furnish the  following  to each  Shareholder
which is a holder of any Series A Preferred  Stock,  Series B Preferred Stock or
any Common Stock Conversion Shares:

                  a. as soon as available  and in any event  within  ninety (90)
days  after the end of each  fiscal  year of the  Company,  a copy of the annual
audit report for such year for the Company, including therein a balance sheet of
the  Company as of the end of such  fiscal year and  statements  of  operations,
shareholders' equity and cash flows of the Company for such fiscal year, setting
forth  in each  case in  comparative  form  the  corresponding  figures  for the
preceding  fiscal year, if any,  together with  supporting  notes  thereto,  all
audited  by  the  Company's  Auditors,  together  with  a  summary  prepared  by
Management concerning the Company's operations and financial condition;

                  b. as soon as  available  and in any event  within  forty-five
(45) days after the end of each  fiscal  quarter of the  Company,  an  unaudited
balance  sheet  of the  Company  as of the end of  such  quarter  and  unaudited
statements of operations, shareholders' equity and cash flows of the Company for
the period ending with such quarter,  setting forth in each case in  comparative
form the corresponding  figures for the corresponding period of the prior fiscal
year duly certified by the chief financial officer of the Company as having been
prepared in accordance  with GAAP applied on a consistent  basis  (provided that
such  unaudited  statements  need not contain  footnotes  and will be subject to
normal year-end adjustments);

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                  c. promptly after  sending,  making  available,  or filing the
same,  all  reports and  financial  statements  that the Company  sends or makes
available to the Shareholders of the Company; and

                  d. to each  holder of at least 5.0% of the Series A  Preferred
Stock, Series B Preferred Stock and any Common Stock Conversion Shares (based on
the total  number of Series A  Preferred  Stock,  Series B  Preferred  Stock and
Common  Stock  Conversion  Shares  then  outstanding),   any  other  information
respecting the business, properties or the condition or operations, financial or
otherwise,  of the Company that any Purchaser  may from time to time  reasonably
request,  including,  but  not  limited  to,  (i)  monthly  unaudited  financial
statements;  (ii) an annual operating plan and budget (including cash flow data)
for the Company for each fiscal year,  prepared in  reasonable  detail,  as such
operating  plan and budget has been  approved by the Board of  Directors  of the
Company, and (iii) comparative information for any month, quarter or fiscal year
relating to the Company's  actual  performance  against the  operating  plan and
budget for the corresponding period.

         15.      CONFIDENTIALITY

                  Any  confidential  information  obtained  by any holder of the
Purchased  Shares pursuant to the Series A Convertible  Preferred Stock Purchase
Agreement of even date hereof, or any other information of a confidential nature
(including,  without  limitation,  the Company's  business  plans,  intellectual
property  and  other  proprietary  rights  or  information  of the  Company)  or
otherwise  identified to such holder as being of a confidential nature, shall be
treated as confidential  and shall not be disclosed to a third party or used for
any  purpose  other than  evaluating  such  holder's  investment  in the Company
without  the  prior  written  consent  of the  Company,  except as  required  by
applicable law or regulation;  provided that any such  confidential  information
may be disclosed to the beneficial  owner of any equity or partnership  interest
in such holder, it being understood that such beneficial owner shall be informed
of the confidential  nature of such  information.  In the event of any breach of
this Section 15, irreparable damage would occur to the Company and, accordingly,
the  Company  shall be  entitled  to  injunctive  relief  and the  right to have
specifically enforced the provisions hereof.

         16.      KEY MAN LIFE INSURANCE

                  The  Company  will  maintain  key man  life  insurance  in the
following amounts:

                  Steven E. Bernstein                $3,000,000
                  Ronald G. Bizick, II               $2,000,000

         17.      ENTIRE AGREEMENT AND AMENDMENTS

                  This  Agreement,  together with the Stock Purchase  Agreement,
constitutes  the entire  agreement  of the parties  with  respect to the subject
matter hereof.  Neither this  Agreement nor any provision  hereof may be waived,
modified,  amended or terminated except by a written agreement signed by (a) the
Company, (b) Mr. Bernstein,  and (c) the holders of not less than 662/3% percent
of the Shares then held by the  Preferred  Shareholders  (based on the number of
shares of Common Stock  Conversion  Shares issued or issuable upon conversion of
the Series A Preferred  Stock). To the extent any term or other provision of any
other  agreement or instrument by which any party hereto is bound conflicts with
this Agreement,  this Agreement shall have precedence over such conflicting term
or provision.

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         IN WITNESS WHEREOF, the parties hereto have caused this Agreement to be
executed as an instrument under seal as of the 6th day of March, 1997.


                               SBA COMMUNICATIONS CORPORATION

                                     /s/ Steven E. Bernstein
                               By:_______________________________
                                  Steven E. Bernstein, President

                                  Address:  SBA Communications Corporation
                                            6001 Broken Sound Parkway
                                            Fourth Floor
                                            Boca Raton, FL  33487

                                             /s/ Steven E. Bernstein
                                            ---------------------------------
                                            Steven E. Bernstein, individually


                                            PURCHASERS

                                            [See Counterpart Signature Pages

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