Form 12b-25                                                         Page 1 of 3
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SEC 1344           Persons who potentially are to respond to the collection of
(7-2000)           information contained in this form are not required to
Previous version   respond unless the form displays a currently valid OMB
obsolete           control number.
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                                  UNITED STATES
                       SECURITIES AND EXCHANGE COMMISSION
                             Washington, D.C. 20549

                                   FORM 12b-25

                           NOTIFICATION OF LATE FILING  SEC FILE NUMBER 0-23717
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(Check One):|_|Form 10-K |_| Form 20-F|_| Form 11-K |X| Form 10-Q|_| Form N-SAR

For Period Ended: September 30, 2001
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         [  ] Transition Report on Form 10-K
         [  ] Transition Report on Form 20-F
         [  ] Transition Report on Form 11-K
         [  ] Transition Report on Form 10-Q
         [  ] Transition Report on Form N-SAR
For the Transition Period Ended:
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  Read Instruction (on back page) Before Preparing Form. Please Print or Type:
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    Nothing in this form shall be construed to imply that the Commission has
                   verified any information contained herein.
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If notification relates to a portion of the filing checked above, identify the
Item(s) to which the notification relates:

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PART 1 - REGISTRANT INFORMATION

Global TeleSystems, Inc.
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Full Name of Registrant

Global TeleSystems Group, Inc.
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Former Name if Applicable

4121 Wilson Boulevard, 7th Floor
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Address of Principal Executive Office (Street and Number)

Arlington, VA 22203
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City, State and Zip Code

PART II - RULES 12 (b) AND (c)

If the subject report could not be filed without unreasonable effort or expense
and the registrant seeks relief pursuant to Rule 12b-25(b), the following should
be completed. (Check box if appropriate)

     |X|       (a) The reasons described in reasonable detail in Part III of
               this form could not be eliminated without unreasonable effort or
               expense;
               (b) The subject annual report, semi-annual report, transition
               report on Form 10-K, Form 20-F, 11-K or Form N-SAR, or
               portion thereof, will be filed on or before the fifteenth
               calendar day following the prescribed due date; or the subject
               quarterly report or transition report on Form 10-Q, or portion
               thereof will be filed on or before the fifth calendar day
               following the prescribed due date; and
               (c) The accountant's statement or other exhibit required by
               Rule 12b-25(c) has been attached if applicable.


Form 12b-25                                                         Page 2 of 3

PART III - NARRATIVE

State below in reasonable detail the reasons why Forms 10-K, 20-F, 11-K, 10-Q,
N-SAR, or the transition report or portion thereof, could not be filed within
the prescribed time period. (Attach Extra Sheets if Needed)

The Form 10-Q for the quarter ended September 30, 2001 could not be filed within
the prescribed time period because the gathering of information in connection
with, as well as the preparation and completion of, the Form 10-Q has required
an unexpectedly substantial amount of time.

The registrant's inability to meet the required filing deadline for the Form
10-Q has been impacted significantly by the implementation of the
registrant's announced November 2000 restructuring that includes, among other
things, the registrant's agreement with KPNQwest N.V., executed as of October
18, 2001, pursuant to which KPNQwest N.V. has agreed to acquire Global
Telesystems Europe B.V. and the registrant's Central European operating
companies (together, the "KPNQwest Acquisition"). During the period since
November 2000, the registrant's management has been substantially engaged on the
restructuring and related initiatives, including, in particular, with KPNQwest
N.V. in connection with the KPNQwest Acquisition. These actions have delayed the
process of gathering the required information that is necessary to complete the
Form 10-Q, as the registrant's management, accounting and financial personnel,
who are an integral part of the effort to complete the Form 10-Q, have had to
focus a substantial amount of time continuously on the restructuring and related
initiatives.

Accordingly, the registrant is unable to file its Form 10-Q in the prescribed
time period without unreasonable effort or expense.


PART IV - OTHER INFORMATION

  (1)    Name and telephone number of person to contact in regard to this
         notification.


       Stephen Baus             011 44              207 769 8106
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           (Name)             (Area Code)        (Telephone Number)


(2) Have all other periodic reports required under Section 13 or 15(d)
of the Securities Exchange Act of 1934 or Section 30 of the Investment
Company Act of 1940 during the preceding 12 months (or for such shorter period
that the registrant was required to file such reports) been filed? If answer no,
identify report(s). |X| Yes |_| No

(3) Is it anticipated that any significant change in results of operations from
the corresponding period for the last fiscal year will be reflected by the
earnings statements to be included in the subject report or portion thereof?
|X| Yes |_| No

If so, attach an explanation of the anticipated change, both narratively and
quantitatively, and, if appropriate, state the reasons why a reasonable estimate
of the results cannot be made.

The registrant expects to report that its operating and net losses for the third
quarter 2001 will be larger than in the third quarter 2000 primarily as a result
of its publicly announced fourth quarter 2000 restructuring initiatives.

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Form 12b-25                                                         Page 3 of 3

                            Global TeleSystems, Inc.
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                  (Name of Registrant as Specified in Charter)

has caused this notification to be signed on its behalf by the undersigned
hereunto duly authorized.

Date  November 14, 2001             By:  /s/ Stephen Baus
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                                    Stephen Baus
                                    Senior Vice President

INSTRUCTION: The form may be signed by an executive officer of the registrant or
by any other duly authorized representative. The name and title of the person
signing the form shall be typed or printed beneath the signature. If the
statement is signed on behalf of the registrant by an authorized representative
(other than an executive officer), evidence of the representative's authority to
sign on behalf of the registrant shall be filed with the form.

                                    ATTENTION

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Intentional misstatements or omissions of fact constitute Federal Criminal
Violations (See 18 U.S.C. 1001).
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                              General Instructions

1. This form is required by Rule 12b-25 (17 CFR 240.12b-25) of the General Rules
and Regulations under the Securities Exchange Act of 1934.
2. One signed original and four conformed copies of this form and amendments
thereto must be completed and filed with the Securities and Exchange Commission,
Washington, D.C. 20549, in accordance with Rule 0-3 of the General Rules and
Regulations under the Act. The information contained in or filed with the form
will be made a matter of public record in the Commission files.
3. A manually signed copy of the form and amendments thereto shall be filed with
each national securities exchange on which any class of securities of the
registrant is registered.
4. Amendments to the notifications must also be filed on form 12b-25 but need
not restate information that has been correctly furnished. The form shall be
clearly identified as an amended notification.
5. Electronic filers. This form shall not be used by electronic filers unable to
timely file a report solely due to electronic difficulties. Filers unable to
submit a report within the time period prescribed due to difficulties in
electronic filing should comply with either Rule 201 or Rule 202 of Regulation
S-T (ss.232.201 or ss.232.202 of this chapter) or apply for an adjustment in
filing date pursuant to Rule 13(b) of Regulation S-T (ss.232.13(b) of this
Chapter).