Washington, D. C. 20549

                                    FORM 8-K

                                 CURRENT REPORT
                     PURSUANT TO SECTION 13 OR 15(d) OF THE
                         SECURITIES EXCHANGE ACT OF 1934

        Date of Report (Date of earliest event reported): April 17, 2006

                                  ADTRAN, Inc.
             (Exact name of registrant as specified in its charter)

          Delaware                  0-24612                   63-0918200
 (State of Incorporation)   (Commission file number)       (I.R.S. Employer
                                                       (Identification Number)

             901 Explorer Boulevard, Huntsville, Alabama 35806-2807
          (Address of principal executive offices, including zip code)

                                 (256) 963-8000
              (Registrant's telephone number, including area code)

Check the appropriate box below if the Form 8-K filing is intended to
simultaneously satisfy the filing obligation of the registrant under any of the
following provisions (see General Instruction A.2. below):

   |_|   Written communications pursuant to Rule 425 under the Securities Act
         (17 CFR 230.425)

   |_|   Soliciting material pursuant to Rule 14a-12 under the Exchange Act (17
         CFR 240.14a-12)

   |_|   Pre-commencement communications pursuant to Rule 14d-2(b) under the
         Exchange Act (17 CFR 240.14d-2(b))

   |_|   Pre-commencement communications pursuant to Rule 13e-4(c) under the
         Exchange Act (17 CFR 240.13e-4(c))

Item 2.02. Results of Operations and Financial Condition.

On April 17, 2006, ADTRAN, Inc. announced its financial results for the fiscal
quarter ended March 31, 2006 and certain other information. ADTRAN also
announced that its Board of Directors declared a quarterly cash dividend. The
quarterly cash dividend is $0.09 per common share to be paid to holders of
record at the close of business on May 4, 2006. The ex-dividend date is May 2,
2006 and the payment date is May 18, 2006. A copy of ADTRAN's press release
announcing such financial results and other information is attached as Exhibit
99.1 hereto and incorporated by reference herein.

Item 9.01. Financial Statements and Exhibits.

             (c)  Exhibits.

             The following exhibit is furnished as part of this Current Report
on Form 8-K.

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

     99.1          Press Release dated April 17, 2006


     Pursuant to the requirements of Section 13 or 15(d) of the Securities
Exchange Act of 1934, the Registrant has duly caused this report to be signed on
its behalf by the undersigned, thereunto duly authorized on April 17, 2006.

                                       ADTRAN, Inc.

                                       By: /s/ James E. Matthews
                                           James E. Matthews
                                           Senior Vice President - Finance,
                                           Chief Financial Officer and Treasurer

                                  EXHIBIT INDEX

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

     99.1          Press Release dated April 17, 2006