<PAGE>   1
   As filed with the Securities and Exchange Commission on February 22, 2001

                                                    Registration No. 333-_______
--------------------------------------------------------------------------------


                       SECURITIES AND EXCHANGE COMMISSION
                             Washington, D.C. 20549

                                    FORM S-8

             REGISTRATION STATEMENT UNDER THE SECURITIES ACT OF 1933

                      FIRST TENNESSEE NATIONAL CORPORATION
             (Exact name of registrant as specified in its charter)


         TENNESSEE                                              62-0803242
(State or other jurisdiction of                              (I.R.S. Employer
incorporation or organization)                              Identification No.)

                               165 MADISON AVENUE
                            MEMPHIS, TENNESSEE 38103
                                 (901) 523-4444
               (Address, including zip code, and telephone number,
                 including area code, of registrant's principal
                               executive offices)

                      FIRST TENNESSEE NATIONAL CORPORATION
                         1997 EMPLOYEE STOCK OPTION PLAN
                              (Full title of plan)

                              HARRY A. JOHNSON, III
                  EXECUTIVE VICE PRESIDENT AND GENERAL COUNSEL
                      FIRST TENNESSEE NATIONAL CORPORATION
                               165 MADISON AVENUE
                            MEMPHIS, TENNESSEE 38103
                                 (901) 523-5624
            (Name, address, including zip code, and telephone number,
                   including area code, of agent for service)

                                  With Copy to:

                             CLYDE A. BILLINGS, JR.
                         SENIOR VICE PRESIDENT & COUNSEL
                      FIRST TENNESSEE NATIONAL CORPORATION
                               165 MADISON AVENUE
                                MEMPHIS, TN 38103
                                 (901) 523-5679


                         CALCULATION OF REGISTRATION FEE

<TABLE>
<CAPTION>
========================================================================================================
Title of Securities to   Amount to be       Proposed Maximum     Proposed Maximum        Amount of
be Registered             Registered       Offering Price per   Aggregate Offering   Registration Fee(1)
                                                Share(1)             Price(1)
--------------------------------------------------------------------------------------------------------
<S>                        <C>                 <C>              <C>                    <C>
Common Stock and           5,000,000           $32.10           $160,500,000           $40,125
Associated Rights
========================================================================================================
</TABLE>

(1) Calculated pursuant to Rule 457(h)(1), based on the average of the high and
low prices reported on the New York Stock Exchange for Registrant's stock on
February 21, 2001.



<PAGE>   2

          On November 15, 1996, Registrant filed a registration statement on
Form S-8 (File No. 333-16225), registering 4,200,000 shares (adjusted for stock
splits) of its common stock, with a current par value of $0.625 per share, for
sale under Registrant's 1997 Employee Stock Option Plan (as amended to date, the
"Plan"). On January 4, 1999, Registrant filed another registration statement on
Form S-8 (File No. 333-70075), registering 6,000,000 additional shares of
Registrant's common stock for sale under the Plan. On November 17, 1999,
Registrant filed another registration statement on Form S-8 (File No.
333-91137), registering 7,000,000 additional shares of Registrant's common stock
for sale under the Plan. Registrant is filing this registration statement to
register 5,000,000 additional shares of Registrant's common stock for sale under
the Plan, which was amended October 18, 2000 to increase by 5,000,000 shares the
shares authorized for issuance.

             PART II. INFORMATION REQUIRED IN REGISTRATION STATEMENT

         As permitted by Instruction E to Form S-8, the contents of Registrant's
registration statement on Form S-8 (File No. 333-16225), which was filed
November 15, 1996, covering shares for sale under the Plan, as updated below,
are incorporated herein by reference. In addition to the foregoing, the
following information is also included in this registration statement:

Item 5.  Interests of Named Experts and Counsel

         The validity of original issue shares of $0.625 par value Common Stock
of First Tennessee National Corporation ("FTNC" or "the Registrant") to be
issued pursuant to the Plan has been passed upon by Clyde A. Billings, Jr.,
Senior Vice President and Counsel of FTNC. Mr. Billings beneficially owns shares
of FTNC common stock and holds options to purchase such shares in an amount
deemed substantial by securities regulations. On January 31, 2001, the number of
shares, including options, beneficially owned by Mr. Billings was approximately
52,000 shares.

Item 6.  Indemnification of Directors and Officers

         Tennessee Code Annotated Sections 48-18-501 through 48-18-509 authorize
a corporation to provide for the indemnification of officers, directors,
employees and agents in terms sufficiently broad to permit indemnification under
certain circumstances for liabilities (including reimbursement for expenses
incurred) arising under the Securities Act of 1933, as amended. FTNC has adopted
the provisions of the Tennessee statute pursuant to Article Six of its Bylaws.
Also FTNC has a "Directors' and Officers' Liability Insurance Policy" which
provides coverage sufficiently broad to permit indemnification under certain
circumstances for liabilities (including reimbursement for expenses incurred)
arising under the Securities Act of 1933, as amended.

         Tennessee Code Annotated, Section 48-12-102, permits the inclusion in
the charter of a Tennessee corporation of a provision, with certain exceptions,
eliminating the personal monetary liability of directors to the corporation or
its shareholders for breach of the duty of care. FTNC has adopted the provisions
of the statute as Article 13 of its charter.

         The shareholders of FTNC have approved an amendment to Article Six of
the Bylaws pursuant to which FTNC is required to indemnify each director and any
officers designated by the Board of Directors, and advance expenses, to the
maximum extent not prohibited by law. In accordance with the foregoing, the
Board of Directors is authorized to enter into individual indemnity agreements
with the directors and such officers. Such indemnity agreements have been
approved for all of the directors and certain officers.

Item 8.  Exhibits

         4(a)     Restated Charter of FTNC, as amended, attached as Exhibit 3(i)
                  to FTNC's Annual Report on Form 10-K for the year ended
                  December 31, 1997 and incorporated herein by reference.

         4(b)     Bylaws of FTNC, as amended and restated, attached as Exhibit
                  3(b) to FTNC's Quarterly Report on Form 10-Q for the quarter
                  ended September 30, 1999 and incorporated herein by reference.




                                      II-1

<PAGE>   3

         4(c)     Shareholder Protection Rights Agreement, dated as of October
                  20, 1998, between FTNC and First Tennessee Bank National
                  Association as Rights Agent, attached as Exhibit 1 to FTNC's
                  registration statement of Form 8-A, filed 10-23-98 and
                  incorporated herein by reference.

         5        Opinion of Clyde A. Billings, Jr. as to legality.

         23(a)    Consent of Arthur Andersen LLP.

         23(b)    Consent of Clyde A. Billings, Jr. (included in Exhibit 5
                  above).

         24       Powers of Attorney.








                                      II-2

<PAGE>   4
                                   SIGNATURES

The Registrant. Pursuant to the requirements of the Securities Act of 1933, the
registrant 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 Memphis and State of Tennessee, on February 22, 2001.


                                    FIRST TENNESSEE NATIONAL CORPORATION



                                    By: Elbert L. Thomas, Jr.
                                        ----------------------------------------
                                        Elbert L. Thomas, Jr.
                                        Executive Vice President and Chief
                                        Financial Officer

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.

<TABLE>
<CAPTION>
Signature                                    Title                               Date
---------                                    -----                               ----

<S>                                 <C>                                          <C>
Ralph Horn*                         Chairman of the Board, President             February 22, 2001
-----------------------------       and Chief Executive Officer
Ralph Horn                          (principal executive officer)
                                    and a Director

Elbert L. Thomas, Jr.*              Executive Vice President                     February 22, 2001
-----------------------------       and Chief Financial Officer
Elbert L. Thomas, Jr.               (principal financial officer)

James F. Keen*                      Senior Vice President                        February 22, 2001
-----------------------------       and Corporate Controller (principal
James F. Keen                       accounting officer)

                                    Director                                     February   , 2001
-----------------------------
Robert C. Blattberg


Carlos H. Cantu*                    Director                                     February 22, 2001
-----------------------------
Carlos H. Cantu


George E. Cates*                    Director                                     February 22, 2001
-----------------------------
George E. Cates


J. Kenneth Glass*                   Director                                     February 22, 2001
-----------------------------
J. Kenneth Glass


James A. Haslam, III*               Director                                     February 22, 2001
-----------------------------
James A. Haslam, III


John C. Kelley, Jr.*                Director                                     February 22, 2001
-----------------------------
John C. Kelley, Jr.


R. Brad Martin*                     Director                                     February 22, 2001
-----------------------------
R. Brad Martin
</TABLE>




                                      II-3

<PAGE>   5



<TABLE>
<S>                                 <C>                                          <C>
Joseph Orgill, III*                 Director                                     February 22, 2001
-----------------------------
Joseph Orgill, III


Vicki R. Palmer*                    Director                                     February 22, 2001
-----------------------------
Vicki R. Palmer


Michael D. Rose*                    Director                                     February 22, 2001
-----------------------------
Michael D. Rose


William B. Sansom*                  Director                                     February 22, 2001
-----------------------------
William B. Sansom


By: Clyde A. Billings, Jr.                                                       February 22, 2001
    -------------------------
    Clyde A. Billings, Jr.
    *As Attorney-in-Fact
</TABLE>






                                      II-4

<PAGE>   6
                                  EXHIBIT INDEX

   Exhibit Table No.
   -----------------

         4(a)     Restated Charter of FTNC, as amended attached as Exhibit 3(i)
                  to FTNC's Annual Report on Form 10-K for the year ended
                  December 31, 1997 and incorporated herein by reference.

         4(b)     Bylaws of FTNC, as amended and restated, attached as Exhibit
                  3(b) to FTNC's Quarterly Report on Form 10-Q for the quarter
                  ended September 30, 1999 and incorporated herein by reference.

         4(c)     Shareholder Protection Rights Agreement, dated as of October
                  20, 1998, between FTNC and First Tennessee Bank National
                  Association as Rights Agent, attached as Exhibit 1 to FTNC's
                  registration statement on Form 8-A, filed 10-23-98 and
                  incorporated herein by reference.

         5        Opinion of Clyde A. Billings, Jr. as to legality.

         23(a)    Consent of Arthur Andersen LLP.

         23(b)    Consent of Clyde A. Billings, Jr. (included in opinion filed
                  as Exhibit 5).

         24       Powers of Attorney.






                                      II-5
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{"company-data": {"conformed-name": "FIRST TENNESSEE NATIONAL CORP", "cik": "0000036966", "assigned-sic": "6021", "irs-number": "620803242", "state-of-incorporation": "TN", "fiscal-year-end": "1231"}, "filing-values": {"form-type": "S-8", "act": "33", "file-number": "333-56052", "film-number": "1552255"}, "business-address": {"street1": "165 MADISON AVE", "city": "MEMPHIS", "state": "TN", "zip": "38103", "phone": "9015234638"}, "mail-address": {"street1": "165 MADISON AVE", "city": "MEMPHIS", "state": "TN", "zip": "38103"}, "former-company": {"former-conformed-name": "FIRST TENNESSEE BANKS INC", "date-changed": "19600201"}}
1
   As filed with the Securities and Exchange Commission on February 22, 2001

                                                    Registration No. 333-_______
--------------------------------------------------------------------------------

                       SECURITIES AND EXCHANGE COMMISSION
                             Washington, D.C. 20549

                                    FORM S-8

             REGISTRATION STATEMENT UNDER THE SECURITIES ACT OF 1933

                      FIRST TENNESSEE NATIONAL CORPORATION
             (Exact name of registrant as specified in its charter)

         TENNESSEE                                              62-0803242
(State or other jurisdiction of                              (I.R.S. Employer
incorporation or organization)                              Identification No.)

                               165 MADISON AVENUE
                            MEMPHIS, TENNESSEE 38103
                                 (901) 523-4444
               (Address, including zip code, and telephone number,
                 including area code, of registrant's principal
                               executive offices)

                      FIRST TENNESSEE NATIONAL CORPORATION
                         1997 EMPLOYEE STOCK OPTION PLAN
                              (Full title of plan)

                              HARRY A. JOHNSON, III
                  EXECUTIVE VICE PRESIDENT AND GENERAL COUNSEL
                      FIRST TENNESSEE NATIONAL CORPORATION
                               165 MADISON AVENUE
                            MEMPHIS, TENNESSEE 38103
                                 (901) 523-5624
            (Name, address, including zip code, and telephone number,
                   including area code, of agent for service)

                                  With Copy to:

                             CLYDE A. BILLINGS, JR.
                         SENIOR VICE PRESIDENT & COUNSEL
                      FIRST TENNESSEE NATIONAL CORPORATION
                               165 MADISON AVENUE
                                MEMPHIS, TN 38103
                                 (901) 523-5679

                         CALCULATION OF REGISTRATION FEE
========================================================================================================
Title of Securities to   Amount to be       Proposed Maximum     Proposed Maximum        Amount of
be Registered             Registered       Offering Price per   Aggregate Offering   Registration Fee(1)
                                                Share(1)             Price(1)
--------------------------------------------------------------------------------------------------------
Common Stock and           5,000,000           $32.10           $160,500,000           $40,125
Associated Rights
========================================================================================================
(1) Calculated pursuant to Rule 457(h)(1), based on the average of the high and
low prices reported on the New York Stock Exchange for Registrant's stock on
February 21, 2001.
2

          On November 15, 1996, Registrant filed a registration statement on
Form S-8 (File No. 333-16225), registering 4,200,000 shares (adjusted for stock
splits) of its common stock, with a current par value of $0.625 per share, for
sale under Registrant's 1997 Employee Stock Option Plan (as amended to date, the
"Plan"). On January 4, 1999, Registrant filed another registration statement on
Form S-8 (File No. 333-70075), registering 6,000,000 additional shares of
Registrant's common stock for sale under the Plan. On November 17, 1999,
Registrant filed another registration statement on Form S-8 (File No.
333-91137), registering 7,000,000 additional shares of Registrant's common stock
for sale under the Plan. Registrant is filing this registration statement to
register 5,000,000 additional shares of Registrant's common stock for sale under
the Plan, which was amended October 18, 2000 to increase by 5,000,000 shares the
shares authorized for issuance.

             PART II. INFORMATION REQUIRED IN REGISTRATION STATEMENT

         As permitted by Instruction E to Form S-8, the contents of Registrant's
registration statement on Form S-8 (File No. 333-16225), which was filed
November 15, 1996, covering shares for sale under the Plan, as updated below,
are incorporated herein by reference. In addition to the foregoing, the
following information is also included in this registration statement:

Item 5.  Interests of Named Experts and Counsel

         The validity of original issue shares of $0.625 par value Common Stock
of First Tennessee National Corporation ("FTNC" or "the Registrant") to be
issued pursuant to the Plan has been passed upon by Clyde A. Billings, Jr.,
Senior Vice President and Counsel of FTNC. Mr. Billings beneficially owns shares
of FTNC common stock and holds options to purchase such shares in an amount
deemed substantial by securities regulations. On January 31, 2001, the number of
shares, including options, beneficially owned by Mr. Billings was approximately
52,000 shares.

Item 6.  Indemnification of Directors and Officers

         Tennessee Code Annotated Sections 48-18-501 through 48-18-509 authorize
a corporation to provide for the indemnification of officers, directors,
employees and agents in terms sufficiently broad to permit indemnification under
certain circumstances for liabilities (including reimbursement for expenses
incurred) arising under the Securities Act of 1933, as amended. FTNC has adopted
the provisions of the Tennessee statute pursuant to Article Six of its Bylaws.
Also FTNC has a "Directors' and Officers' Liability Insurance Policy" which
provides coverage sufficiently broad to permit indemnification under certain
circumstances for liabilities (including reimbursement for expenses incurred)
arising under the Securities Act of 1933, as amended.

         Tennessee Code Annotated, Section 48-12-102, permits the inclusion in
the charter of a Tennessee corporation of a provision, with certain exceptions,
eliminating the personal monetary liability of directors to the corporation or
its shareholders for breach of the duty of care. FTNC has adopted the provisions
of the statute as Article 13 of its charter.

         The shareholders of FTNC have approved an amendment to Article Six of
the Bylaws pursuant to which FTNC is required to indemnify each director and any
officers designated by the Board of Directors, and advance expenses, to the
maximum extent not prohibited by law. In accordance with the foregoing, the
Board of Directors is authorized to enter into individual indemnity agreements
with the directors and such officers. Such indemnity agreements have been
approved for all of the directors and certain officers.

Item 8.  Exhibits

         4(a)     Restated Charter of FTNC, as amended, attached as Exhibit 3(i)
                  to FTNC's Annual Report on Form 10-K for the year ended
                  December 31, 1997 and incorporated herein by reference.

         4(b)     Bylaws of FTNC, as amended and restated, attached as Exhibit
                  3(b) to FTNC's Quarterly Report on Form 10-Q for the quarter
                  ended September 30, 1999 and incorporated herein by reference.

                                      II-1
3

         4(c)     Shareholder Protection Rights Agreement, dated as of October
                  20, 1998, between FTNC and First Tennessee Bank National
                  Association as Rights Agent, attached as Exhibit 1 to FTNC's
                  registration statement of Form 8-A, filed 10-23-98 and
                  incorporated herein by reference.

         5        Opinion of Clyde A. Billings, Jr. as to legality.

         23(a)    Consent of Arthur Andersen LLP.

         23(b)    Consent of Clyde A. Billings, Jr. (included in Exhibit 5
                  above).

         24       Powers of Attorney.

                                      II-2
4
                                   SIGNATURES

The Registrant. Pursuant to the requirements of the Securities Act of 1933, the
registrant 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 Memphis and State of Tennessee, on February 22, 2001.

                                    FIRST TENNESSEE NATIONAL CORPORATION

                                    By: Elbert L. Thomas, Jr.
                                        ----------------------------------------
                                        Elbert L. Thomas, Jr.
                                        Executive Vice President and Chief
                                        Financial Officer

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
---------                                    -----                               ----
Ralph Horn*                         Chairman of the Board, President             February 22, 2001
-----------------------------       and Chief Executive Officer
Ralph Horn                          (principal executive officer)
                                    and a Director

Elbert L. Thomas, Jr.*              Executive Vice President                     February 22, 2001
-----------------------------       and Chief Financial Officer
Elbert L. Thomas, Jr.               (principal financial officer)

James F. Keen*                      Senior Vice President                        February 22, 2001
-----------------------------       and Corporate Controller (principal
James F. Keen                       accounting officer)

                                    Director                                     February   , 2001
-----------------------------
Robert C. Blattberg

Carlos H. Cantu*                    Director                                     February 22, 2001
-----------------------------
Carlos H. Cantu

George E. Cates*                    Director                                     February 22, 2001
-----------------------------
George E. Cates

J. Kenneth Glass*                   Director                                     February 22, 2001
-----------------------------
J. Kenneth Glass

James A. Haslam, III*               Director                                     February 22, 2001
-----------------------------
James A. Haslam, III

John C. Kelley, Jr.*                Director                                     February 22, 2001
-----------------------------
John C. Kelley, Jr.

R. Brad Martin*                     Director                                     February 22, 2001
-----------------------------
R. Brad Martin
II-3
5
Joseph Orgill, III*                 Director                                     February 22, 2001
-----------------------------
Joseph Orgill, III

Vicki R. Palmer*                    Director                                     February 22, 2001
-----------------------------
Vicki R. Palmer

Michael D. Rose*                    Director                                     February 22, 2001
-----------------------------
Michael D. Rose

William B. Sansom*                  Director                                     February 22, 2001
-----------------------------
William B. Sansom

By: Clyde A. Billings, Jr.                                                       February 22, 2001
    -------------------------
    Clyde A. Billings, Jr.
    *As Attorney-in-Fact
II-4
6
                                  EXHIBIT INDEX

   Exhibit Table No.
   -----------------

         4(a)     Restated Charter of FTNC, as amended attached as Exhibit 3(i)
                  to FTNC's Annual Report on Form 10-K for the year ended
                  December 31, 1997 and incorporated herein by reference.

         4(b)     Bylaws of FTNC, as amended and restated, attached as Exhibit
                  3(b) to FTNC's Quarterly Report on Form 10-Q for the quarter
                  ended September 30, 1999 and incorporated herein by reference.

         4(c)     Shareholder Protection Rights Agreement, dated as of October
                  20, 1998, between FTNC and First Tennessee Bank National
                  Association as Rights Agent, attached as Exhibit 1 to FTNC's
                  registration statement on Form 8-A, filed 10-23-98 and
                  incorporated herein by reference.

         5        Opinion of Clyde A. Billings, Jr. as to legality.

         23(a)    Consent of Arthur Andersen LLP.

         23(b)    Consent of Clyde A. Billings, Jr. (included in opinion filed
                  as Exhibit 5).

         24       Powers of Attorney.

                                      II-5