<PAGE>   1

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

                                    FORM 10-Q

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


 For the Quarter Ended September 30, 2000       Commission File No. 001-10887



                               JENNY CRAIG, INC.
--------------------------------------------------------------------------------
             (Exact name of registrant as specified in its charter)



         DELAWARE                                       33-0366188
--------------------------------------------------------------------------------
(State of Incorporation)                    (I.R.S. Employer Identification No.)



11355 NORTH TORREY PINES ROAD, LA JOLLA, CA                  92037
--------------------------------------------------------------------------------
(Address of principal executive offices)                  (Zip Code)



        Registrant's telephone number, including area code (858) 812-7000

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 [X] No [ ]

Number of shares of common stock, $.000000005 par value, outstanding as of the
close of business on November 10, 2000 - 20,688,971.


                                      -1-
<PAGE>   2

ITEM 1. FINANCIAL STATEMENTS

                       JENNY CRAIG, INC. AND SUBSIDIARIES
                           CONSOLIDATED BALANCE SHEETS
                                ($ in thousands)
<TABLE>
<CAPTION>
                                                                             June 30,     September 30,
                                                                               2000            2000
                                                                            ---------       ---------
                                                                                            (unaudited)
<S>                                                                         <C>               <C>
ASSETS
Cash and cash equivalents ............................................      $  34,710          34,139
Short-term investments ...............................................            925              --
Accounts receivable, net .............................................          2,271           1,973
Inventories ..........................................................         11,785          10,932
Prepaid expenses and other assets ....................................          5,625           6,094
Deferred tax assets ..................................................            864             864
                                                                            ---------       ---------
                Total current assets .................................         56,180          54,002
Deferred tax assets ..................................................         16,696          14,535
Cost of reacquired area franchise rights and other intangibles, net ..          8,658           8,219
Property and equipment, net ..........................................         25,797          24,817
Other assets .........................................................            630             535
                                                                            ---------       ---------
                                                                            $ 107,961         102,108
                                                                            =========       =========

LIABILITIES AND STOCKHOLDERS' EQUITY
Accounts payable .....................................................      $  13,473          12,545
Accrued liabilities ..................................................         15,515          15,119
Current installments of obligation under capital lease ...............            642             652
Accrual  for litigation judgment .....................................          9,649           9,868
Deferred service revenue .............................................         10,175          10,052
                                                                            ---------       ---------
                 Total current liabilities ...........................         49,454          48,236
Note payable, excluding current installments .........................          5,147           5,100
Obligation under capital lease, excluding current installments .......          1,732           1,511
                                                                            ---------       ---------
                 Total liabilities ...................................         56,333          54,847

Stockholders' equity:
    Common stock $.000000005 par value, 100,000,000 shares authorized;
        27,580,260 shares issued; 20,688,971 shares
        outstanding at June 30, 2000 and September 30, 2000 ..........             --              --
    Additional paid-in capital .......................................         71,622          71,622
    Retained earnings ................................................         49,415          47,679
    Accumulated other comprehensive income ...........................          5,353           2,722
    Treasury stock, at cost: 6,891,289 shares at June 30, 2000 and
        September 30, 2000 ...........................................        (74,762)        (74,762)
                                                                            ---------       ---------
                Total stockholders' equity ...........................         51,628          47,261
Commitments and contingencies ........................................
                                                                            ---------       ---------
                                                                            $ 107,961         102,108
                                                                            =========       =========
</TABLE>

     See accompanying notes to unaudited consolidated financial statements.


                                      -2-
<PAGE>   3

                       JENNY CRAIG, INC. AND SUBSIDIARIES
                 UNAUDITED CONSOLIDATED STATEMENTS OF OPERATIONS
                   ($ in thousands, except per share amounts)


<TABLE>
<CAPTION>
                                                             Three Months Ended
                                                                September 30,
                                                           ----------------------
                                                             1999          2000
                                                           --------      --------
<S>                                                        <C>             <C>
Revenues:
     Company-owned operations:
         Product sales...............................      $ 61,501        57,103
         Service revenue .............................        4,153         4,253
                                                           --------      --------
                                                             65,654        61,356
                                                           --------      --------
     Franchise operations:
         Product sales ...............................        5,045         4,251
         Royalties ...................................          802           711
         Initial franchise fees ......................           10            75
                                                           --------      --------
                                                              5,857         5,037
                                                           --------      --------
                Total revenues .......................       71,511        66,393
                                                           --------      --------
Costs and expenses:
     Company-owned operations:
         Product .....................................       63,945        56,099
         Service .....................................        3,071         3,101
                                                           --------      --------
                                                             67,016        59,200
                                                           --------      --------
     Franchise operations:
         Product .....................................        3,374         3,051
         Other .......................................          534           257
                                                           --------      --------
                                                              3,908         3,308
                                                           --------      --------
                                                                587         3,885
General and administrative expenses ..................        6,286         5,593
Litigation judgment ..................................          789           219
                                                           --------      --------
         Operating loss ..............................       (6,488)       (1,927)
Other income, net, principally interest ..............          387           345
                                                           --------      --------
         Loss before income taxes ....................       (6,101)       (1,582)
Income taxes (benefit) ...............................       (2,319)          154
                                                           --------      --------
            Net loss .................................     $ (3,782)       (1,736)
                                                           ========      ========

          Basic and diluted net loss per share .......     $   (.18)         (.08)
                                                           ========      ========
</TABLE>





     See accompanying notes to unaudited consolidated financial statements.


                                      -3-
<PAGE>   4

                       JENNY CRAIG, INC. AND SUBSIDIARIES
                 UNAUDITED CONSOLIDATED STATEMENTS OF CASH FLOWS
                                ($ in thousands)

<TABLE>
<CAPTION>
                                                                                 Three Months Ended
                                                                                   September 30,
                                                                               ----------------------
                                                                                 1999          2000
                                                                               --------      --------
<S>                                                                            <C>             <C>
Cash flows from operating activities:
    Net loss .............................................................     $ (3,782)       (1,736)
    Adjustments to reconcile net loss to net cash  provided
      by (used in) operating activities:
      Depreciation and amortization ......................................        1,493         1,372
      Provision for deferred income taxes (benefit) ......................       (3,263)        2,161
      Loss on write-off of cost of reacquired area franchise rights ......           94           209
      Loss on disposal of property and equipment .........................            4             1
      (Increase) decrease in:
              Accounts receivable ........................................         (125)          298
              Inventories ................................................          181           853
              Prepaid expenses and other assets ..........................        2,523          (374)
      Increase (decrease) in:
              Accounts payable ...........................................          291          (928)
              Accrued liabilities ........................................         (330)         (396)
              Accrual for litigation judgment ............................          789           219
              Income taxes payable .......................................           --            --
              Deferred service revenue ...................................           83          (123)
                                                                               --------      --------
                       Net cash provided by (used in) operating activities       (2,042)        1,556
                                                                               --------      --------

Cash flows from investing activities:
   Purchase of property and equipment ....................................       (1,461)         (163)
   Purchase of short-term investments ....................................       (1,850)           --
   Proceeds from maturity of short-term investments ......................        1,379           925
                                                                               --------      --------
                       Net cash provided by (used in) investing activities       (1,932)          762
                                                                               --------      --------

Cash flows from financing activities:
   Principal payments on note payable and capital lease ..................          (47)         (258)
                                                                               --------      --------

Effect of exchange rate changes on cash and cash equivalents .............          479        (2,631)
                                                                               --------      --------
Net decrease in cash and cash equivalents ................................       (3,542)         (571)
Cash and cash equivalents at beginning of period .........................       38,864        34,710
                                                                               --------      --------
Cash and cash equivalents at end of period ...............................     $ 35,322        34,139
                                                                               ========      ========

Supplemental disclosure of cash flow information:
   Income taxes paid .....................................................     $  1,276           465
   Interest paid .........................................................           91           156
Supplemental disclosure of investing activities:
   Equipment acquired under capital lease ................................        2,727            --
</TABLE>


     See accompanying notes to unaudited consolidated financial statements.


                                      -4-
<PAGE>   5


                       JENNY CRAIG, INC. AND SUBSIDIARIES
              NOTES TO UNAUDITED CONSOLIDATED FINANCIAL STATEMENTS
                               September 30, 2000

1.   The accompanying unaudited consolidated financial statements do not include
all of the information and footnotes required by generally accepted accounting
principles for complete financial statements. In the opinion of management, all
adjustments, consisting only of normal recurring adjustments, considered
necessary for a fair presentation have been included. Operating results for any
interim period are not necessarily indicative of the results for any other
interim period or for the full year. These statements should be read in
conjunction with the June 30, 2000 consolidated financial statements.

2.   The weighted average number of shares used to calculate basic net loss per
share was 20,688,971 for the quarters ended September 30, 1999 and 2000. The
calculation of diluted net loss per share for the quarters ended September 30,
1999 and 2000 excluded the effect of 2,167,000 and 2,462,000 stock options,
respectively, as their effect would be antidilutive.

3.   Comprehensive loss for the quarters ended September 30, 1999 and 2000
presented below includes foreign currency translation items. There was no tax
expense or tax benefit associated with the foreign currency items.

<TABLE>
<CAPTION>
                                                          Three Months Ended
                                                             September 30,
                                                       ------------------------
                                                         1999             2000
                                                       -------          -------
<S>                                                    <C>               <C>
Net loss                                               $(3,782)          (1,736)
Foreign currency translation adjustments                   479           (2,631)
                                                       -------          -------
Comprehensive loss                                     $(3,303)          (4,367)
                                                       =======          =======
</TABLE>


                                      -5-
<PAGE>   6

                       JENNY CRAIG, INC. AND SUBSIDIARIES
              NOTES TO UNAUDITED CONSOLIDATED FINANCIAL STATEMENTS
                                  (Continued)


4.   The Company operates in the weight management industry. Substantially all
revenue results from the sale of weight management products and services,
whether the centre is operated by the Company or its franchisees. The Company's
reportable segments consist of Company-owned operations and franchise
operations, further segmented by geographic area. The following presents
information about the respective reportable segments ($ in thousands):

<TABLE>
<CAPTION>
                                                            Three Months
                                                         Ended September 30,
                                                      1999                2000
                                                    --------             ------
<S>                                                 <C>                  <C>
Revenue:
       Company-owned operations:
             United States                          $ 52,029             51,733
             Foreign                                  13,625              9,623
       Franchise operations:
             United States                             3,546              3,613
             Foreign                                   2,311              1,424
Operating income (loss):
       Company-owned operations:
             United States                           (10,053)            (3,281)
             Foreign                                   2,527                481
       Franchise operations:
             United States                               181                428
             Foreign                                     857                445
Identifiable assets:
       United States                                  97,529             86,728
       Foreign                                        15,295             15,380
</TABLE>


                                      -6-
<PAGE>   7


ITEM 2.   MANAGEMENT'S DISCUSSION AND ANALYSIS OF FINANCIAL CONDITION AND
          RESULTS OF OPERATIONS

Forward-Looking Statements

        Information provided in this Report on Form 10-Q may contain, and the
Company may from time to time disseminate material and make statements which may
contain "forward-looking" information, as that term is defined by the Private
Securities Litigation Reform Act of 1995 (the "Act"). These forward-looking
statements may relate to anticipated financial performance, business prospects
and similar matters. The words "expects," "anticipates," "believes," and similar
words generally signify a "forward-looking" statement. These cautionary
statements are being made pursuant to the provisions of the Act and with the
intention of obtaining the benefit of "safe-harbor" provisions of the Act. The
reader is cautioned that all forward-looking statements are necessarily
speculative and there are certain risks and uncertainties that could cause
actual events or results to differ materially from those referred to in such
forward-looking statements. Among the factors that could cause actual results to
differ materially are: increased competition; technological and scientific
developments, including appetite suppressants and other drugs which can be used
in weight-loss programs; increases in cost of food or services; lack of market
acceptance of additional products and services; legislative and regulatory
restrictions or actions; effectiveness of marketing and advertising programs;
prevailing domestic and foreign economic conditions; and the risk factors set
forth from time to time in the Company's annual reports and other reports and
filings with the SEC. The reader should carefully review the cautionary
statements contained under the caption "Forward-Looking Statements" in Item 1 of
the Company's Annual Report on Form 10-K for the year ended June 30, 2000.

Quarter Ended September 30, 2000 as Compared to Quarter Ended September 30, 1999

The following table presents selected operating results for United States
Company-owned and foreign Company-owned operations for the quarters ended
September 30, 1999 and 2000 (U.S. $ in thousands):

<TABLE>
<CAPTION>
                                       U.S. Company Owned                      Foreign Company Owned
                                           Operations                               Operations
                                   Three Months Ended Sept. 30,             Three Months Ended Sept. 30,
                                ----------------------------------        -------------------------------
                                                              %                                       %
                                  1999            2000      Change         1999          2000      Change
                                ----------------------------------        -------------------------------
<S>                             <C>              <C>        <C>           <C>            <C>       <C>
Product sales                   $ 48,810         48,256       -1%         12,691         8,847      -30%
Service revenue                    3,219          3,477        8%            934           776      -17%
                                -----------------------                   --------------------
Total                             52,029         51,733       -1%         13,625         9,623      -29%
Costs and expenses                56,581         50,770      -10%         10,435         8,430      -19%
General and administrative         4,712          4,025      -15%            663           712        7%
Litigation judgment                  789            219        -               -             -        -
                                -----------------------                   --------------------
Operating income (loss)         $(10,053)        (3,281)      67%          2,527           481      -81%
                                -----------------------                   --------------------
Average number of centres            526            435      -17%            110           113        3%
                                -----------------------                   --------------------
</TABLE>


                                      -7-
<PAGE>   8

                MANAGEMENT'S DISCUSSION AND ANALYSIS OF FINANCIAL
                       CONDITION AND RESULTS OF OPERATIONS
                                   (Continued)


               Revenues from United States Company-owned operations, which
represented 79% of the worldwide Company-owned centres at September 30, 2000,
decreased 1% for the quarter ended September 30, 2000 compared to the quarter
ended September 30, 1999. The decrease in revenues from United States
Company-owned operations was the result of a 17% decrease in the average number
of United States Company-owned centres in operation, offset, in part by a 20%
increase in the average revenue per United States Company-owned centre, from
$99,000 for the quarter ended September 30, 1999 to $119,000 for the quarter
ended September 30, 2000. The decrease in the number of United States
Company-owned centres reflects the closure of 89 centres between the periods,
principally comprised of the closure of 86 centres in November 1999 in
connection with a restructuring plan implemented by the Company. Product sales,
which consists primarily of food products, from United States Company-owned
operations decreased 1% principally due to a 5% decrease in the number of active
participants in the program between the periods. Service revenues from United
States Company-owned operations increased 8% principally due to an increase in
the average service fee charged per new participant.

            Revenues from foreign Company-owned operations, which is derived
from 87 centres in Australia and 26 centres in Canada, decreased 29% principally
due to reduced demand at the Company's Australian centres. The Company believes
that the introduction of Xenical, a prescription drug for the treatment of
obesity, in May 2000 and a new goods and services tax in the Australian market
have contributed to the revenue decline. There was a 12% weighted average
decrease in the Australian and Canadian currencies in relation to the U.S.
dollar between the periods.

            Costs and expenses of United States Company-owned operations
decreased 10% for the quarter ended September 30, 2000 compared to the same
quarter last year. The quarter ended September 30, 1999 included a charge of
$3,068,000 for obsolete inventory related to the discontinued On-the-Go program.
The 10% decrease was principally due to the reduced fixed costs associated with
the decrease in the number of United States Company-owned centres in operation,
and the absence of the charge of $3,068,000 for obsolete inventory. Costs and
expenses of United States Company-owned operations as a percentage of United
States Company-owned revenues decreased from 109% to 98% between the periods
principally due to the reduced fixed costs and the absence of the aforementioned
charge for discontinued inventory. After including the allocable portion of
general and administrative expenses, United States Company-owned operations had
an operating loss of $3,281,000 for the quarter ended September 30, 2000
compared to an operating loss of $10,053,000 for the quarter ended September 30,
1999.

            Costs and expenses of foreign Company-owned operations decreased 19%
for the quarter ended September 30, 2000 compared to the quarter ended September
30, 1999, principally due to the decreased variable costs associated with the
decreased revenues from the Australian operations and the 12% weighted average
decrease in the Australian and Canadian currencies in relation to the U.S.
dollar between the periods. After including the allocable portion of general and
administrative expenses, foreign Company-owned operations had operating income
of $481,000 for the quarter ended September 30, 2000 compared to operating
income of $2,527,000 for the quarter ended September 30, 1999.

          Revenues from franchise operations decreased 14% from $5,857,000 to
$5,037,000 for the quarters ended September 30, 1999 and 2000, respectively.
This decline was principally due to a 6% decrease in the average number of
franchise centres in operation between the periods and a


                                      -8-
<PAGE>   9

                MANAGEMENT'S DISCUSSION AND ANALYSIS OF FINANCIAL
                       CONDITION AND RESULTS OF OPERATIONS
                                   (Continued)


decrease in the revenues at foreign franchised centres which resulted in reduced
product sales and royalties for the Company. The decrease in the average number
of franchise centres reflects the Company's net acquisition of six centres from
franchisees between the periods. As of September 30, 2000 there were 111
franchised centres in operation, of which 73 were in the United States and 38
were in foreign countries, principally Australia and New Zealand.

           Costs and expenses of franchised operations, which consist primarily
of product costs, decreased 15% from $3,908,000 to $3,308,000 for the quarters
ended September 30, 1999 and 2000, respectively, principally because of the
reduced level of franchise operations. Franchise costs and expenses as a
percentage of franchise revenues remained relatively constant between the
periods.

           General and administrative expenses decreased 11% from $6,286,000 to
$5,593,000 and decreased from 8.8% to 8.4% of total revenues for the quarters
ended September 30, 1999 and 2000, respectively. The decrease in general and
administrative expenses is principally due to reduced legal and consulting
expenses.

           A charge of $219,000 was recorded in the accompanying consolidated
statement of operations in the quarter ended September 30, 2000 with respect to
the previously disclosed litigation judgment arising out of the dispute
concerning the lease at the Company's former headquarters location. This charge
consists of interest accrued on the judgment pending the appeal which has been
filed seeking to overturn the judgment. At September 30, 2000 the total amount
accrued for this litigation judgment was $9,868,000.

           The elements discussed above combined to result in an operating loss
of $1,927,000 for the quarter ended September 30, 2000 compared to an operating
loss of $6,488,000 for the quarter ended September 30, 1999.

           Income taxes (benefit) for the quarter ended September 30, 2000
includes income taxes at an effective rate of 37% on the Company's foreign
taxable income, but does not reflect any benefit for the net operating loss
incurred by the Company's United States operations.

Financial Condition

           At September 30, 2000, the Company had cash, cash equivalents, and
short-term investments totaling $34,139,000 compared to $35,635,000 at June 30,
2000. The decrease in cash, cash equivalents, and short-term investments
resulted principally from the operating loss for the period. The Company
believes that its cash, cash equivalents, and short-term investments and its
cash flow from operations will be adequate for its needs in the foreseeable
future.


                                      -9-
<PAGE>   10

                MANAGEMENT'S DISCUSSION AND ANALYSIS OF FINANCIAL
                       CONDITION AND RESULTS OF OPERATIONS
                                   (Continued)


Recent Accounting Pronouncements

               In June 1998, the Financial Accounting Standards Board issued
Statement of Financial Accounting Standards No. 133, "Accounting for Derivative
Instruments and Hedging Activities" ("SFAS 133"), which establishes accounting
and reporting standards for derivative instruments and hedging activities. SFAS
133, as amended by SFAS 137, requires the recognition of all derivative
instruments as either assets or liabilities in the balance sheet and measurement
of those derivative instruments at fair value. SFAS 133 was amended by SFAS 137
which defers the effective date to all fiscal quarters of fiscal years beginning
after June 15, 2000. The adoption of SFAS 133, as amended, is not expected to
have a material impact on the Company's financial position or results of
operations.

               In December 1999, the Securities and Exchange Commission issued
Staff Accounting Bulletin No. 101 ("SAB 101"), "Revenue Recognition in Financial
Statements". The Company will be required to adopt SAB 101, as amended, in the
fourth quarter of fiscal 2001. SAB 101 requires, among other things, that
up-front fees be recognized over the term of the agreement, unless the fees are
in exchange for products delivered or services performed that represent the
culmination of a separate earnings process. The Company does not expect this to
have a material impact on the Company's financial position or results of
operations.


                                      -10-
<PAGE>   11

ITEM 3.   QUANTITATIVE AND QUALITATIVE DISCLOSURES ABOUT MARKET
          RISK

      The Company is exposed to a variety of risks, including changes in
interest rates affecting the return on its investments and the cost of its debt,
and foreign currency fluctuations.

      At September 30, 2000, the Company maintains a portion of its cash and
cash equivalents in financial instruments with original maturities of three
months or less. The Company also, at times, maintains a short-term investment
portfolio containing financial instruments with original maturities of greater
than three months but less than twelve months. These financial instruments,
principally comprised of high quality commercial paper, are subject to interest
rate risk and will decline in value if interest rates increase. Due to the short
duration of these financial instruments, an immediate 10 percent increase in
interest rates would not have a material effect on the Company's financial
condition or results of operations. The Company has not used derivative
financial instruments in its investment portfolio.

       The Company's long-term debt at September 30, 2000 is comprised of a note
payable to a bank, secured by the Company's corporate office building, with a
total balance of $5,290,000 and a capital lease agreement covering certain
computer hardware with a total balance of $2,163,000. The note payable bears
interest at the London Interbank Offered Rate plus one percent, with quarterly
interest rate adjustments, and the capital lease is at a fixed rate. Due to the
relative immateriality of the long-term debt, an immediate 10 percent change in
interest rates would not have a material effect on the Company's financial
condition or results of operations.

       Approximately 17% of the Company's revenues for the quarter ended
September 30, 2000 were generated from foreign operations, located principally
in Australia and Canada. In the quarter ended September 30, 2000, the Company
was subjected to a 12% weighted average decrease in the Australian and Canadian
currencies in relation to the U.S. dollar compared to the quarter ended
September 30, 1999. Currently, the Company does not enter into forward exchange
contracts or other financial instruments with respect to foreign currency.


                                      -11-
<PAGE>   12

PART II - OTHER INFORMATION

Item 6. Exhibits and Reports on Form 8-K.

<TABLE>
<CAPTION>
     (a)  Exhibits
          --------
<S>                      <C>
             27.         Financial Data Schedule
</TABLE>

     (b)  No reports on Form 8-K have been filed during the quarter for which
          this report is filed.

-----------


                                      -12-
<PAGE>   13

                                    SIGNATURE

      Pursuant to the requirements 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.

                                JENNY CRAIG, INC.

                                By: /s/ James S. Kelly
                                   ------------------------------
                                   James S. Kelly
                                   Vice President,
                                   Chief Financial Officer, and Treasurer



Date:  November 13, 2000

                                      -13-