UNITED STATES
                       SECURITIES AND EXCHANGE COMMISSION
                             Washington, D.C. 20549

                                   FORM 10-K/A

|X| ANNUAL REPORT PURSUANT TO SECTION 13 OR 15(D) OF THE SECURITIES EXCHANGE ACT
    OF 1934

                  For the fiscal year ended December 31, 2000.

                                       OR

|_| TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(D) OF THE SECURITIES EXCHANGE
    ACT OF 1934

                       For the transition period from   to

                        Commission File Number 000-23387

                                 TELIGENT, INC.
             (Exact Name of Registrant as Specified in its Charter)

                   Delaware                              54-1866562
       (State or other jurisdiction of     (I.R.S. Employer Identification No.)
        incorporation or organization)

             460 Herndon Parkway                            20170
                  Suite 100                               (Zip Code)
                 Herndon, VA
   (Address of principal executive offices)

       Registrant's telephone number, including area code: (703) 326-4400

           Securities registered pursuant to Section 12(b) of the Act:

                                      None

           Securities registered pursuant to Section 12(g) of the Act:

                         11 1/2 % Senior Notes due 2007
                     11 1/2 % Senior Discount Notes due 2008
                 Common Stock, Class A, par value $.01 per share

     Indicate by check mark whether the registrant: (1) has filed all reports
required to be filed by Section 13 or 15(d) of the Securities Exchange Act of
1934 during the preceding 12 months (or for such shorter period that the
registrant was required to file such reports), and (2) has been subject to such
filing requirements for the past 90 days: Yes |_| No|X|.

     Indicate by check mark if disclosure of delinquent filers pursuant to Item
405 of Regulation S-K is not contained herein, and will not be contained, to the
best of the registrant's knowledge, in the definitive proxy or information
statements incorporated by reference in Part III of this Form 10-K or any
amendment to this Form 10-K|_|.

     The aggregate market value of the registrant's voting stock held by
non-affiliates of the registrant was approximately $27 million on March 26,
2001, based on the closing sales price of the registrant's Class A Common Stock
as reported on The Nasdaq Stock Market as of such date.

     The number of shares outstanding of each of the registrant's classes of
common stock as of March 26, 2001 was as follows:

                        Common Stock, Class A 42,583,265
                        Common Stock, Class B 21,260,610
<PAGE>

     (c) Exhibits.   The following exhibits are filed as a part of this Annual
Report on Form 10-K:

3.1      Form of Certificate of Incorporation of Registrant, filed as Exhibit
         3.1 to the Company's Registration Statement on Form S-1 (Registration
         No. 333-37381), dated November 26, 1997, and incorporated herein by
         reference.

3.2      Form of By-laws of Registrant, filed as Exhibit 3.2 to the Company's
         Registration Statement on Form S-1 (Registration No. 333-37381), dated
         November 26, 1997, and incorporated herein by reference.

3.3      Certificate of Designation of the Powers, Preferences and Relative,
         Participating, Optional and other Special Rights of 7 3/4% Cumulative
         Convertible Preferred Stock and Qualifications, Limitations and
         Restrictions Thereof, filed as Exhibit 10.4 to the Company's Current
         Report on Form 8-K, dated January 18, 2000, and incorporated herein by
         reference.

4.1      Form of Stockholders Agreement, filed as Exhibit 4.1 to the Company's
         Registration Statement on Form S-1 (Registration No. 333-37381), dated
         November 26, 1997, and incorporated herein by reference.

4.2      Form of Indenture between the Registrant, as issuer, and First Union
         National Bank, as Trustee, relating to Registrant's Senior Notes due
         2007, including form of Note, filed as Exhibit 4.2 to the Company's
         Registration Statement on Form S-1 (Registration No. 333-37381), dated
         November 26, 1997, and incorporated herein by reference.

4.3      Form of Pledge Agreement between Registrant, as issuer, and First Union
         National Bank, as Escrow Agent, relating to Registrant's Senior Notes
         due 2007, filed as Exhibit 4.3 to the Company's Registration Statement
         on Form S-1 (Registration No. 333-37381), dated November 26, 1997, and
         incorporated herein by reference.

4.4      Form of Indenture between the Registrant, as issuer, and First Union
         National Bank, as Trustee, relating to Registrant's Senior Discount
         Notes due 2008, including form of Note, filed as Exhibit 4.4 to the
         Company's Annual Report on Form 10-K filed with the Commission on March
         31, 1998, and incorporated herein by reference.

4.5      Form of Certificate for the Class A common stock, filed as Exhibit 4.4
         to the Company's Registration Statement on Form S-1 (Registration No.
         333-37381), dated November 26, 1997, and incorporated herein by
         reference.

4.6      Stockholders Agreement, dated as of January 13, 2000, by and among Alex
         J. Mandl, Liberty Media Corporation, Telcom--DTS Investors, L.L.C., and
         Microwave Services, Inc., filed as Exhibit 10.1 to the Company's
         Current Report on Form 8-K, dated January 18, 2000, and incorporated
         herein by reference.

4.7      Stock Purchase Warrant, dated as of December 7, 2000, by the registrant
         in favor of RGC International Investors, LDC, filed as Exhibit 10.3 to
         the Company's Current Report on Form 8-K, dated December 21, 2000, and
         incorporated herein by reference.

10.1     Employment Agreement, dated August 19, 1996, between Associated
         Communications, L.L.C. and Alex J. Mandl, filed as Exhibit 10.1 to the
         Company's Registration Statement on Form S-1 (Registration No. 333-
         37381), dated November 26, 1997, and incorporated herein by reference.

10.2     Stock Contribution Agreement, dated as of March 10, 1997, among
         Associated Communications, L.L.C., FirstMark Communications, Inc. and
         Lynn Forester, filed as Exhibit 10.2 to the Company's Registration
         Statement on Form S-1 (Registration No. 333-37381), dated November 26,
         1997, and incorporated herein by reference.

10.3     Securities Purchase Agreement, dated as of September 30, 1997, by and
         among Teligent, L.L.C., Microwave Services, Inc., Digital Services
         Corporation, and Nippon Telegraph and Telephone Corporation, filed as
         Exhibit 10.3 to the Company's Registration Statement on Form S-1
         (Registration No. 333-37381), dated November 26, 1997, and incorporated
         herein by reference.

                                       2
<PAGE>

10.4     Form of Registration Rights Agreement, by and among Teligent, L.L.C.
         and Nippon Telegraph and Telephone Corporation, filed as Exhibit 10.4
         to the Company's Registration Statement on Form S-1(Registration No.
         333-37381), dated November 26, 1997, and incorporated herein by
         reference.

10.5     Form of Technical Services Agreement, by and among Teligent, L.L.C. and
         NTT America, Inc., filed as Exhibit 10.5 to the Company's Registration
         Statement on Form S-1 (Registration No. 333-37381), dated November 26,
         1997, and incorporated herein by reference.

10.6     Agreement, dated September 29, 1997, among Teligent, L.L.C., Digital
         Services Corporation, Telcom-DTS Investors, L.L.C., Microwave Services,
         Inc., The Associated Group, Inc. and certain other parties, filed as
         Exhibit 10.6 to the Company's Registration Statement on Form S-1
         (Registration No. 333-37381), dated November 26, 1997, and incorporated
         herein by reference.

10.7     Agreement and Plan of Merger, dated as of October 6, 1997, by and
         between Teligent, Inc. and Teligent, L.L.C., filed as Exhibit 10.7 to
         the Company's Registration Statement on Form S-1 (Registration No. 333-
         37381), dated November 26, 1997, and incorporated herein by reference.

10.8     Form of Lease Agreement, dated as of July 22, 1997, for the 8065
         Leesburg Pike, Vienna, Virginia office space lease between NHP
         Incorporated and Teligent, L.L.C., filed as Exhibit 10.8 to the
         Company's Registration Statement on Form S-1 (Registration No.
         333-37381), dated November 26, 1997, and incorporated herein by
         reference.

10.9     Form of Teligent, Inc. 1997 Stock Incentive Plan, as amended and
         restated, filed as Exhibit 4.4 to the Company's Registration Statement
         on Form S-8 (Registration No. 333-93241), dated December 31, 1999, and
         incorporated herein by reference.

10.10    Network Products Purchase Agreement, dated December 11, 1997, by and
         between Northern Telcom Inc. and Teligent, Inc., filed as Exhibit 10.10
         to the Company's Annual Report on Form 10-K filed with the Commission
         on March 31, 1997, and incorporated herein by reference. [Confidential
         treatment has been granted for portions of this document].

10.11    Credit Agreement, dated July 2, 1998 among Teligent, Inc., several
         banks and other financial institutions or entities, Chase Securities,
         Inc., Goldman Sashes Credit Partners L.P. and TD Securities (USA) Inc.,
         as advisers and arrangers, Goldman Sachs Credit Partners L.P., as
         syndication agent, The Chase Manhattan Bank, as administrative agent
         and Toronto Dominion (Texas), Inc. as documentation agent. Filed as
         Exhibit 10 to the Company's Form 8-K, filed on August 13, 1998, and
         incorporated herein by reference. [Confidential treatment has been
         granted for portions of this document].

10.12    Promissory Note, dated February 1, 1997, by Kirby G. Pickle, Jr. to
         Associated Communications, L.L.C., filed as Exhibit 10.10 to the
         Company's Registration Statement (Registration No. 333-37381), dated
         November 26, 1997, and incorporated herein by reference.

10.13    Promissory Notes, each dated October 29, 1997, by Abraham L. Morris to
         Teligent, L.L.C., filed as Exhibit 10.11 to the Company's Registration
         Statement on Form S-1 (Registration No. 333-37381), dated November 26,
         1997, and incorporated herein by reference.

10.14    Promissory Note, dated August 5, 1997, by Laurence E. Harris to
         Associated Communications, L.L.C., filed as Exhibit 10.12 to the
         Company's Registration Statement on Form S-1 (Registration No. 333-
         37381), dated November 26, 1997, and incorporated herein by reference.

10.15    Promissory Note, dated April 7, 1997, by Steven F. Bell to Associated
         Communications, L.L.C., filed as Exhibit 10.14 to the Company's
         Registration Statement on Form S-1 (Registration No. 333-37381), dated
         November 26, 1997, and incorporated herein by reference.

10.16    Registration rights agreement, dated as of March 6, 1998, by and
         between Teligent, Inc., and Microwave Services, Inc., filed as Exhibit
         10.16 to the Company's Annual Report on Form 10-K, filed with the
         Commission on March 31, 1998, and incorporated herein by reference.
                                       3
<PAGE>

10.17    Registration rights agreement, dated as of February 20, 1998, by and
         between Teligent, Inc. and Merrill Lynch, Pierce, Fenner & Smith
         Incorporated ("Merrill Lynch"), Goldman Sachs & Co., Salomon Brothers
         Inc., and TD Securities (USA) Inc., filed as Exhibit 10.17 to the
         Company's Annual Report on Form 10-K, filed with the Commission on
         March 31, 1998, and incorporated herein by reference.

10.18    Equipment Purchase Definitive Agreement, dated December 18, 1998, by
         and between Teligent, Inc. and Hughes Network Systems, filed as Exhibit
         10 to the Company's Current Report on Form 8-K, filed with the
         Commission on April 19, 1999, and incorporated herein by reference.
         [Confidential treatment has been granted for portions of this
         document].

10.19    Teligent, Inc. 1999 Employee Stock Purchase Plan, filed as Exhibit 4.5
         to the Company's Registration Statement on Form S-8 (Registration No.
         333-93241), dated December 21, 1999, and incorporated herein by
         reference.

10.20    Stock Purchase Agreement, dated as of November 4, 1999, between the
         Issuer and the Purchasers (as defined in the Stock Purchase Agreement)
         named on Schedule I thereto, relating to the purchase and sale of
         7 3/4% Series A Convertible Preferred Stock of Teligent, Inc, filed as
         Exhibit 10.2 to the Company's Current Report on Form 8-K, dated January
         18, 2000, and incorporated herein by reference.

10.21    Registration Rights Agreement, dated as of November 4, 1999, between
         the Issuer and each of the Initial Holders (as defined in the
         Registration Rights Agreement), filed as Exhibit 10.3 to the Company's
         Current Report on Form 8-K, dated January 18, 2000, and incorporated
         herein by reference.

10.22    Common Stock Purchase Agreement, dated as of December 7, 2000, by and
         between the registrant and RGC International Investors, LDC, filed as
         Exhibit 10.1 to the Company's Current Report on Form 8-K, dated
         December 21, 2000, and incorporated herein by reference.

10.23    Registration Rights Agreement, dated as of December 7, 2000, by and
         among the registrant and RGC International Investors, LDC, filed as
         Exhibit 10.2 to the Company's Current Report on Form 8-K, dated
         December 21, 2000, and incorporated herein by reference.

10.24    Agreement, dated as of May 9, 2000, by and between Level 3
         Communications, LLC and Teligent Services, Inc., as amended, filed as
         Exhibit 10.1 to the Company's Quarterly Report on Form 10-Q, filed with
         the Commission on November 14, 2000, and incorporated herein by
         reference. [Portions of the document have been omitted pursuant to a
         request for confidential treatment requested through November 1, 2005.]

10.25    Amendment and Consent, dated as of March 30, 2001, to the Credit
         Agreement, dated as of July 2, 1998, among Teligent, Inc., lenders from
         time to time parties thereto, Goldman Sachs Credit Partners L.P., as
         syndication agent, Toronto Dominion (Texas), Inc., as documentation
         agent, and The Chase Manhattan Bank, as administrative agent.

12.1     Statement regarding computation of ratios, filed as Exhibit 12.1 to the
         Company's Annual Report on Form 10-K, dated March 30, 2001, and
         incorporated herein by reference.

12.2     Statement regarding computation of ratios, filed as Exhibit 12.2 to the
         Company's Annual Report on Form 10-K, dated March 30, 2001, and
         incorporated herein by reference.

21.1     Significant Subsidiaries of the Registrant, filed as Exhibit 21.1 to
         the Company's Annual Report on Form 10-K, dated March 30, 2001, and
         incorporated herein by reference.

23.1     Consent of Independent Auditors dated June 29, 2001.

99.1     Press release of Teligent, Inc. dated February 28, 2001, filed as
         Exhibit 99.1 to the Company's Annual Report on Form 10-K, dated March
         30, 2001, and incorporated herein by reference.

                                       4
<PAGE>


                                   SIGNATURES

         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.

                                        TELIGENT, INC.
                                        (Registrant)


Date:  February 13, 2002                By: /s/ James V. Continenza
                                           -----------------------------
                                           James V. Continenza
                                           Chief Operating Officer and Director
                                           (Principal Executive Officer)


                                       5