EXHIBIT 5.1

                   OPINION OF JOHN L. GARDNER, GENERAL COUNSEL

                                November 6, 1998

Inter-Tel, Incorporated
120 North 44th Street, Suite 200
Phoenix, Arizona 85304-1822

     Re:  REGISTRATION STATEMENT ON FORM S-8


Ladies and Gentlemen:


In  connection  with the  registration  under  the  Securities  Act of 1933 (the
"Securities  Act")  pursuant  to a  Registration  Statement  of  Form  S-8  (the
"Registration  Statement") of 82,428 shares (the  "Shares") of Common Stock,  no
par value, of Inter-Tel,  Incorporated,  an Arizona corporation (the "Company"),
under the Company's  Acquisition Stock Option Plan (the "Plans"),  I, as General
Counsel of the Company, have examined the Registration Statement, such corporate
records,  certificates and other documents, and such questions of law, as I have
considered  necessary or appropriate for the purposes of this opinion.  Upon the
basis of such  examination,  I advise you that,  in my opinion,  when issued and
sold in the manner  described in the Plans and pursuant to the agreements  which
accompany  each grant  under the Plans,  the Shares  will be legally and validly
issued, fully paid and assessable.

The foregoing  opinion is limited to the laws of the state of Arizona,  and I am
expressing no opinion as to the effect of the laws of any other jurisdiction.

I do  hereby  consent  to the  filing  of  this  opinion  as an  exhibit  to the
Registration Statement and any amendments thereto.



                                          Very truly yours,

                                          /s/ John L. Gardner, General Counsel