EXHIBIT 5
                    [LONG ALDRIDGE & NORMAN LLP LETTERHEAD]

                                 July 27, 2001

Board of Directors
ADTRAN, Inc.
901 Explorer Boulevard
Huntsville, Alabama 35814-4000

   Re:    ADTRAN, Inc. Amended and Restated 1996 Employees Incentive Stock
          Option Plan
          Registration Statement on Form S-8

Ladies and Gentlemen:

   We have acted as counsel to ADTRAN, Inc., a Delaware corporation (the
"Company"), in connection with a Registration Statement on Form S-8 (the
"Registration Statement") and the filing thereof with the Securities and
Exchange Commission (the "Commission").  Pursuant to the Registration Statement,
the Company intends to register under the Securities Act of 1933, as amended, a
total of 3,000,000 shares of the Company's Common Stock, par value $.01 per
share (the "Plan Shares"), which are issuable upon the exercise of options which
may be granted in the future pursuant to the ADTRAN, Inc. Amended and Restated
1996 Employees Incentive Stock Option Plan (the "Plan").

   The opinion hereinafter set forth is given at the request of the Company
pursuant to Item 8 of Form S-8 and Item 601(b)(5) of Regulation S-K.  The only
opinion rendered by this firm consists of the matter set forth in numbered
paragraph (1) below (our "Opinion"), and no opinion is implied or to be inferred
beyond such matters.  Additionally, our Opinion is based upon and subject to the
qualifications, limitations and exceptions set forth in this letter.

   Our Opinion is furnished for the benefit of the Company solely with regard to
the Registration Statement, may be relied upon by the Company only in connection
with the Registration Statement and may not otherwise be relied upon, used,
quoted or referred to by or filed with any other person or entity without our
prior written permission.

   In rendering our Opinion, we have examined such agreements, documents,
instruments and records as we deemed necessary or appropriate under the
circumstances for us to express our Opinion, including, without limitation, the
record of corporate proceedings and the Plan.  In making all of our
examinations, we assumed the genuineness of all signatures, the authenticity of
all documents submitted to us as originals, the conformity to the original
documents of all documents submitted to us as copies, and the due execution and
delivery of all documents by any persons or entities where due execution and
delivery by such persons or entities is a prerequisite to the effectiveness of
such documents.

   As to various factual matters that are material to our Opinion, we have
relied upon the factual statements set forth in a certificate of officers of the
Company.  We have not independently verified or investigated, nor do we assume
any responsibility for, the factual accuracy or completeness of such factual
statements.

   The members of this firm are admitted to the Bar of the State of Georgia and
are duly qualified to practice law in that state.  We do not herein express any
opinion concerning any matter respecting or affected by any laws other than
provisions of the General Corporation Law of the State of Delaware as now in
effect and that, in the exercise of reasonable professional judgment, are
normally considered in transactions such as the issuance of the Plan Shares.
The Opinion hereinafter set forth is based upon pertinent laws and facts in
existence as of the date


hereof, and we expressly disclaim any obligation to advise you of changes to
such pertinent laws or facts that hereafter may come to our attention.

   Based upon and subject to the foregoing, we are of the following opinion:

   (1)    the Plan Shares, when issued upon the exercise of options, in
          accordance with the terms of the Plan, against payment in full of the
          option exercise price therefor, will be validly issued, fully paid and
          nonassessable.

     We hereby consent to the filing of this letter as an exhibit to the
Registration Statement.

                                    Very truly yours,

                                    Long Aldridge  & Norman LLP


                                    By: /s/ Thomas P. Lauth
                                        -------------------
                                        Thomas P. Lauth