As filed with the Securities and Exchange Commission on November 13, 1998
                                                  Registration No. 33-__________
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                       SECURITIES AND EXCHANGE COMMISSION
                             WASHINGTON, D.C. 20549

                                   ----------

                                    FORM S-8
                             REGISTRATION STATEMENT
                                      UNDER
                           THE SECURITIES ACT OF 1933

                                   ----------


                             INTER-TEL, INCORPORATED
             ------------------------------------------------------
             (Exact name of registrant as specified in its charter)


         ARIZONA                                                  86-0220994
- ----------------------------                                 -------------------
(State or other jurisdiction                                    (IRS Employer
     of incorporation)                                       Identification No.)


                        120 North 44th Street, Suite 200
                           Phoenix, Arizona 85304-1822
                    ----------------------------------------
                    (Address of principal executive offices)

                                   ----------

                          ACQUISITION STOCK OPTION PLAN
                          -----------------------------
                            (Full Title of the Plan)

                                   ----------

                                STEVEN G. MIHAYLO
         Chairman of the Board of Directors and Chief Executive Officer
                             INTER-TEL, INCORPORATED
                        120 North 44th Street, Suite 200
                           Phoenix, Arizona 85304-1822
                     ---------------------------------------
                     (Name and address of agent for service)


                                 (602) 302-8900
          -------------------------------------------------------------
          (Telephone number, including area code, of agent for service)


                                   Copies to:
                           PATRICK J. SCHULTHEIS, ESQ.
                       WILSON, SONSINI, GOODRICH & ROSATI
                            Professional Corporation
                               650 Page Mill Road
                        Palo Alto, California 94304-1050

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========================================================================================
                                                              
  Title of                  Amount        Proposed           Proposed         Amount of
Securities to               to be     Maximum Offering   Maximum Aggregate  Registration
be Registered             Registered  Price Per Share     Offering Price         Fee
- ----------------------------------------------------------------------------------------
Common Stock, no par
value per share, to
be issued upon exercise
of options granted            82,428         $ 9.85(1)         $811,916          $240.00
under the Acquisition
Stock Option Plan
- ----------------------------------------------------------------------------------------
     TOTALS                   82,428                           $811,916          $240.00
========================================================================================


(1)  Under the  Acquisition  Stock Option Plan (the  "Plan"),  82,428 shares are
     subject to outstanding  options to purchase the Company's Common Stock. The
     Proposed  Maximum  Offering  Price Per Share with  respect  to such  82,428
     shares was  calculated  pursuant  to Rule 457(h) of the  Securities  Act of
     1933, as amended (the "Securities  Act") by reference to the exercise price
     of such options.  The weighted average exercise price of such 82,428 shares
     subject to outstanding options under the Plan is $9.85.


                                     PART II

               INFORMATION REQUIRED IN THE REGISTRATION STATEMENT

ITEM 3. INFORMATION INCORPORATED BY REFERENCE.

     There are hereby  incorporated by reference in this Registration  Statement
the following documents and information heretofore filed with the Securities and
Exchange Commission:

     (a) The  Registrant's  Annual Report on Form 10-K filed pursuant to Section
13 or 15(d) of the  Securities  Exchange Act of 1934, as amended (the  "Exchange
Act"), on 3/30/98.

     (b) The  description  of the  Registrant's  Common  Stock  contained in the
Registrant's  Registration  Statement on Form 8-A dated February 26, 1982, filed
pursuant  to Section 12 of the  Securities  Exchange  Act of 1934,  as  amended,
including  any  amendment  or report  filed for the  purpose  of  updating  such
description.  All documents filed by the Registrant  pursuant to Sections 13(a),
13(c),  14 and 15(d) of the  Exchange  Act  after the date of this  registration
statement and prior to the filing of a post-effective  amendment which indicates
that all securities  offered have been sold or which  deregisters all securities
then remaining  unsold,  shall be deemed to be incorporated by reference in this
registration  statement  and to be part  hereof  from  the date of  filing  such
documents.

     (c) All  reports  and  other  documents  filed by  Registrant  pursuant  to
Sections  13(a),  13(c), 14 and 15(d) of the Exchange Act after the date hereof,
and prior to the filing of a  post-effective  amendment which indicates that all
securities offered hereunder have been sold or which de-registers all securities
then remaining unsold under this registration  statement,  shall be deemed to be
incorporated  by reference  herein and to be part hereof from the date of filing
of such reports and documents.

ITEM 4. DESCRIPTION OF SECURITIES.

        Not applicable.

ITEM 5. INTERESTS OF NAMED EXPERTS AND COUNSEL.

        Not applicable.

ITEM 6. INDEMNIFICATION OF DIRECTORS AND OFFICERS.

     The Company's  Restated  Articles of  Incorporation  limit,  to the maximum
extent  permitted  by Arizona law,  the  personal  liability  of  directors  for
monetary  damages  for  breach  of their  fiduciary  duties as a  director.  The
Company's  Restated  Articles of  Incorporation  provide that the Company  shall
indemnify  its officers and  directors to the fullest  extent  permitted by law,
subject to certain  exceptions.  The Company has  entered  into  indemnification
agreements with its officers and directors  containing  provisions  which are in
some respects broader than the specific indemnification  provisions contained in
the Arizona Revised  Statutes.  The  indemnification  agreements may require the
Company,  among other things,  to indemnify such officers and directors  against
certain  liabilities  that may  arise by reason of their  status or  service  as
directors or officers (other than liabilities arising from willful misconduct of
a  culpable  nature),  to advance  their  expenses  incurred  as a result of any
proceeding  against  them as to which they could be  indemnified,  and to obtain
directors'  and  officers'  insurance,  if available on  reasonable  terms.  The
Company  believes  that these  agreements  are  necessary  to attract and retain
qualified persons as directors and officers.

     At present,  there is no pending  litigation  or  proceeding  involving any
director,  officer,  employee or agent of the Company where indemnification will
be required or permitted.  The Company is not aware of any threatened litigation
or proceeding which may result in a claim or such indemnification.

     The  Company  currently   maintains   directors'  and  officers'  liability
insurance.

     Reference  is  also  made  to  Section  11 of  the  Underwriting  Agreement
contained in Exhibit 1.1 to the amendment to the Company's S-3 filed on November
20, 1997,  indemnifying officers and directors of the Registrant against certain
liabilities.

ITEM 7. EXEMPTION FROM REGISTRATION CLAIMED.

        Not applicable.

ITEM 8. EXHIBITS.

        Exhibit
        Number
        ------
        *4.1    Certificate of Incorporation of the Registrant

        *4.2    Bylaws of the Registrant

         5.1    Opinion of John L. Gardner,  General Counsel, as to the legality
                of securities being registered

        10.1    Acquisition Stock Option Plan and Form of Stock Option Agreement
                thereunder

                                      II-2

        23.1    Consent of Independent Auditors

        23.2    Consent of Counsel (included in Exhibit 5.1)

        24.1    Power of Attorney (see page II-4)

- ----------
*  Incorporated by reference to the Registrant's  Registration Statement on Form
   S-3 (File No. 333-39221) (the  "Registration  Statement"),  filed pursuant to
   the Securities Act of 1933, as amended (the "Securities Act"),  including the
   Amended Prospectus dated November 20, 1997 included therein.

All other exhibits for which  provision is made in Item 601 of Regulation S-K of
the  Securities  Act are  either not  required  under the  instructions  related
thereto or are inapplicable, and therefore have been omitted.

ITEM 9. UNDERTAKINGS.

     (a) The undersigned Registrant hereby undertakes:

         (1) To file, during any period in which offers or sales are being made,
a  post-effective  amendment  to this  registration  statement  to  include  any
material  information  with respect to the plan of  distribution  not previously
disclosed  in  the  registration  statement  or  any  material  change  to  such
information in the registration statement.

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

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

     (b) The  undersigned  Registrant  hereby  undertakes  that, for purposes of
determining  any  liability  under  the  Securities  Act,  each  filing  of  the
Registrant's  annual  report  pursuant to Section  13(a) or Section 15(d) of the
Exchange Act (and, where  applicable,  each filing of an employee benefit plan's
annual  report   pursuant  to  Section  15(d)  of  the  Exchange  Act)  that  is
incorporated by reference in the registration  statement shall be deemed to be a
new registration  statement relating to the securities offered therein,  and the
offering of such  securities at that time shall be deemed to be the initial bona
fide offering thereof.

     (c) Insofar as indemnification for liabilities arising under the Securities
Act of 1933 may be permitted to directors,  officers and controlling  persons of
the Registrant pursuant to the Registrant's Bylaws,  indemnification agreements,
or  otherwise,  the  Registrant  has been  advised  that in the  opinion  of the
Securities and Exchange Commission such indemnification is against public policy
as expressed in the Act and is,  therefore,  unenforceable.  In the event that a
claim for  indemnification  against such liabilities  (other than the payment by
the  Registrant  of  expenses  incurred  or  paid  by  a  director,  officer  or
controlling  person of the Registrant in the  successful  defense of any action,
suit or proceeding) is asserted by such director,  officer or controlling person
in connection with the securities being registered,  the Registrant will, unless
in the  opinion  of its  counsel  the matter  has been  settled  by  controlling
precedent,  submit to a court of appropriate  jurisdiction  the question whether
such  indemnification by it is against public policy as expressed in the Act and
will be governed by the final adjudication of such issue.

                                      II-3

                                   SIGNATURES

     Pursuant to the requirements of the Securities Act of 1933, the Registrant,
Inter-Tel,   Incorporated,  an  Arizona  corporation,   certifies  that  it  has
reasonable  grounds to believe that it meets all of the  requirements for filing
on Form S-8 and has duly caused this registration  statement to be signed on its
behalf by the undersigned,  thereunto duly  authorized,  in the City of Phoenix,
State of Arizona, on November 12, 1998.

                                       INTER-TEL, INCORPORATED

                                       By: /s/ Kurt R. Kneip
                                          --------------------------------------
                                          Kurt R. Kneip, Chief Financial Officer

                                POWER OF ATTORNEY

     KNOW ALL  PERSONS  BY THESE  PRESENTS,  that each  person  whose  signature
appears  below  constitutes  and  appoints  Steven G. Mihaylo and Kurt R. Kneip,
jointly  and  severally,   his   attorneys-in-fact,   each  with  the  power  of
substitution,  for him in any and all capacities, to sign any amendments to this
Registration  Statement on Form S-8, and to file the same, with exhibits thereto
and other  documents in connection  therewith,  with the Securities and Exchange
Commission,   hereby   ratifying   and   confirming   all  that   each  of  said
attorneys-in-fact,  or his substitute or substitutes, may do or cause to be done
by virtue hereof.

     Pursuant  to  the   requirements  of  the  Securities  Act  of  1933,  this
registration  statement  has  been  signed  by  the  following  persons  in  the
capacities and on the date indicated.

      SIGNATURE                       TITLE                          DATE
      ---------                       -----                          ----

/s/ Steven G. Mihaylo         Chairman of the Board and        November 12, 1998
- ---------------------------   Chief Executive Officer
   (Steven G. Mihaylo)        (Principal Executive Officer)

/s/ Kurt R. Kneip             Chief Financial Officer          November 12, 1998
- ---------------------------   (Principal Financial and
   (Kurt R. Kneip)            Accounting Officer)

/s/ Gary D. Edens             Director                         November 12, 1998
- ---------------------------
   (Gary D. Edens)

/s/ Maurice H. Esperseth      Director                         November 12, 1998
- ---------------------------
   (Maurice H. Esperseth)

/s/ C. Roland Haden           Director                         November 12, 1998
- ---------------------------
   (C. Roland Haden)


/s/ J. Robert Anderson        Director                         November 12, 1998
- ---------------------------
   (J. Robert Anderson)


                                      II-4


                       SECURITIES AND EXCHANGE COMMISSION

                             WASHINGTON, D.C. 20549

                              --------------------

                                    EXHIBITS

                              --------------------


                       REGISTRATION STATEMENT ON FORM S-8

                             INTER-TEL, INCORPORATED

                                NOVEMBER 13, 1998


                                INDEX TO EXHIBITS


       Exhibit
       Number                       Description
       ------                       -----------

        5.1     Opinion of John L. Gardner, General Counsel

        10.1    Acquisition Stock Option Plan and Form of Stock Option Agreement
                thereunder

        23.1    Consent of Independent Auditors

        23.2    Consent  of John  L.  Gardner,  General  Counsel  (Contained  in
                Exhibit 5.1)

        24.1    Power of Attorney (See page II-4)