<PAGE>
 
                                 UNITED STATES
                       SECURITIES AND EXCHANGE COMMISSION

                              Washington, DC 20548


                                   FORM 10-Q/A
                               (AMENDMENT NO. 1)
    [X]  QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES
                              EXCHANGE ACT OF 1934
                  For the quarterly period ended June 30, 1998


    [_]  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: 0-25674


                        CBT GROUP PUBLIC LIMITED COMPANY
             (Exact name of registrant as specified in its charter)



          Republic of Ireland                            Not Applicable
   ----------------------------------------------------------------------
   (State or other jurisdiction of                      (I.R.S. Employer
    incorporation or organization)                     Identification No.) 


                             900 Chesapeake Drive
                           Redwood City, California  94063
          (Address of principal executive offices, including zip code)


                                 (650) 817-5900
              (Registrant's telephone number, including area code)


Indicate by check mark whether 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 Registrant was required
to file such reports), and (2) has been subject to such filing requirements for
the past ninety (90) days.

                                Yes [X]  No [_]

The number of American Depositary Shares (issued or issuable in exchange for
Registrant's issued and outstanding Ordinary Shares) outstanding as of July 29,
1998 was 43,881,451.

                                       1
<PAGE>
 
                        CBT GROUP PUBLIC LIMITED COMPANY

                               TABLE OF CONTENTS

                                                                        Page
                                                                       Number
                                                                       ------
PART I.  FINANCIAL INFORMATION

         Item 1. Financial Statements

                 Condensed Consolidated Balance Sheets as of
                 December 31, 1997 and as of June 30, 1998                  3

                 Condensed Consolidated Statements of
                 Operations for the three and six month
                 periods ended June 30, 1997 and 1998                       4

                 Condensed Consolidated Statements of Cash
                 Flows for the six month periods ended June
                 30, 1997 and 1998                                          5

                 Notes to Condensed Consolidated Financial
                 Statements                                                 6

         This quarterly report on form 10-Q/A ("Form 10-Q/A") is being filed as
         Amendment No. 1 to the Registrant's Quarterly Report on Form 10-Q filed
         with the Securities and Exchange Commission on August 14, 1998 ("Form
         10-Q") for the purpose of amending Item 1 to include additional
         disclosure in the Notes to Condensed Consolidated Financial Statements.

                                       2
<PAGE>
 
PART I FINANCIAL INFORMATION
ITEM 1 FINANCIAL STATEMENTS

 
                                 CBT GROUP PLC
                     CONDENSED CONSOLIDATED BALANCE SHEETS
                            (dollars in thousands)
<TABLE>
<CAPTION> 
                                                                 DECEMBER 31,             JUNE 30,
                                                                     1997                   1998
                                                                   --------               --------
                                                                                         (Unaudited)
<S>                                                              <C>                     <C>   
                            ASSETS                                                       
Current assets
--------------
Cash                                                               $ 35,506               $ 45,577
Short term investments                                               36,038                 36,091
Accounts receivable, net                                             40,030                 44,009
Inventories                                                             615                  1,021
Deferred tax assets, net                                                140                    142
Prepaid expenses                                                      4,198                  8,458
                                                                   --------               --------
             Total Current assets                                   116,527                135,298
Intangible assets                                                     5,600                  4,878
Property and equipment, net                                          10,207                 14,345
Investment                                                              200                    350
Deferred tax assets, net                                                342                     47
Other assets                                                          8,453                 12,023
                                                                   --------               --------
             Total  assets                                          141,329                166,941
                                                                   ========               ========
               LIABILITIES AND SHAREHOLDERS EQUITY
Current Liabilities
-------------------
Borrowings under bank overdraft facility and overdrafts                  13                     13
Accounts Payable                                                      4,820                  6,296
Accrued payroll and related expenses                                  6,411                  3,785
Other accrued liabilities                                            16,715                 17,491
Deferred revenues                                                     4,551                  1,075
                                                                   --------               --------
             Total Current Liabilities                               32,510                 28,660
Non Current Liabilities
-----------------------
Other accrued liabilities                                               519                    474
Minority equity interest                                                622                    622
                                                                   --------               --------
             Total Non Current Liabilities                            1,141                  1,096
Shareholders' Equity
--------------------
Ordinary Shares: 30,000,000 shares authorized , IR37.5p par           6,372                  6,571
 value, at December 31, 1997 and 120,0000 shares
 authorized, par value IR9.375p at June 30, 1998;
Issued and outstanding:10,511,190 shares at December 31,
 1997 and 43,249,900 shares at June 30, 1998
Additional paid-in-capital                                           97,868                115,745
Accumulated surplus                                                   2,984                 14,425
Deferred Compensation                                                  (112)                     -
Treasury Stock                                                           (2)                    (2)
Cumulative translation adjustment                                       568                    446
                                                                   --------               --------
             Total Shareholders' equity                             107,678                137,185
                                                                   --------               --------
Total Liabilities and shareholders' equity                          141,329                166,941
                                                                   ========               ========
</TABLE>
Note:  The condensed consolidated balance sheet at December 31, 1997 has been
derived from the audited financial statements at that date and has been restated
to reflect the acquisition of The ForeFront Group, Inc (see note 2 below). In
addition, the balance sheet does not include all of the information and
footnotes required by generally accepted accounting principles for complete
financial statements.

                                       3
<PAGE>
 
                                 CBT GROUP PLC
                                        
                Condensed Consolidated Statements of Operations
                (dollars in thousands, except per share amounts)
                                        
<TABLE>
<CAPTION>
                                                         Three Months                        Six Months
                                               --------------------------------  ----------------------------------
                                                        Ended June 30,                     Ended June 30,
                                               --------------------------------  ----------------------------------
                                                    1997             1998              1997              1998
                                               ---------------  ---------------  ----------------  ----------------
                                                 (Unaudited)     (Unaudited)        (Unaudited)      (Unaudited)
<S>                                            <C>              <C>              <C>               <C>
Revenues                                              $29,755          $44,852           $56,482           $84,781
Cost of revenues                                        5,173            6,697             9,854            12,641
                                                      -------          -------           -------           -------
Gross profit                                           24,582           38,155            46,628            72,140
Operating expenses:
  Research and development                              4,731            6,604             9,162            12,994
  Sales and marketing                                  13,415           18,622            26,243            35,490
  General and administrative                            3,616            3,594             5,964             6,808
  Acquired research and development                       447               --               447                --
  Cost of acquisitions                                     --            5,505               926             5,505
                                                      -------          -------           -------           -------
    Total operating expenses                           22,209           34,325            42,742            60,797
                                                      -------          -------           -------           -------
Income from operations                                  2,373            3,830             3,886            11,343
Other income, net                                         665              936             1,220             1,903
                                                      -------          -------           -------           -------
Income before provision for income taxes                3,038            4,766             5,106            13,246
Provision for income taxes                                817              667             1,336             1,805
                                                      -------          -------           -------           -------
Net income                                              2,221            4,099             3,770            11,441
                                                      =======          =======           =======           =======
Net income per equivalent ADS (1) - Basic               $0.06            $0.09             $0.09             $0.27
                                                      =======          =======           =======           =======
ADSs used in computing net income per                  39,923           43,283            39,690            42,939
 equivalent ADS - Basic                               =======          =======           =======           =======
Net income per equivalent ADS (1) - Diluted             $0.05            $0.09             $0.09             $0.25
                                                      =======          =======           =======           =======
ADSs used in computing net income per equivalent       43,938           46,357            43,757            46,080
                                                      =======          =======           =======           =======
</TABLE>

(1)  Net income per equivalent ADS gives effect to the two-for-one share split
     of Registrants' ADSs effected March 1998. Prior periods have been restated
     to give effect to such split.

                                       4
<PAGE>
 
                                 CBT GROUP PLC

                CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS
                          INCREASE (DECREASE) IN CASH
                            (dollars in thousands)



                                                Six Months Ended June 30,
                                                   1997         1998
                                                -----------  -----------
                                                (Unaudited)  (Unaudited)
 
CASH FLOW FROM OPERATING ACTIVITIES
Net income                                         $ 3,770      $11,441
Adjustments to reconcile net income to
 net cash provided by operating activities:
   Depreciation and amortization                     1,671        2,958
   Loss on Disposal of Assets                                        70
   Accrued interest on short-term investments         (222)         236
   Compensation Expense                                 51          112
Changes in operating assets and Liabilities:
   Accounts receivable                              (3,928)      (4,114)
   Inventories                                        (150)        (410)
   Deferred Tax Assets                                  --          293
   Non Cash acquired R&D costs                         447           --
   Prepaid expenses and other assets                (3,285)      (7,885)
   Accounts payable                                   (391)       1,541
   Accrued payroll and related expenses
     and other accrued liabilities                   2,338       (1,784)
   Deferred revenues                                (2,251)      (3,455)
                                                   -------      -------
Net cash provided by operating activities           (1,950)        (997)
                                                   -------      -------

CASH FLOWS FROM INVESTING ACTIVITIES
 Purchase of property and equipment                 (2,096)      (6,499)
 Payments to acquire short-term investments           (248)     (50,330)
 Proceeds from short-term investments                   --       50,041
 Proceeds from disposal of property and equipment       --           20
 Payments to acquire Investments                        --         (150)
                                                    ------       ------
 Net cash used in investing activities              (2,344)      (6,918)
                                                    ------       ------
 
CASH FLOWS FROM FINANCING ACTIVITIES
 Repayment of bank loans                              (794)          --
 Repayments under bank overdraft facility             (138)          --
 Proceeds from issuance of preferred shares 
   in subsidiary                                       605           --
 Proceeds from issuance of ordinary shares, 
   net                                               5,106       18,076
                                                     -----       ------
Net cash (used in) provided by financing 
  activities                                         4,779       18,076
                                                     -----       ------
Effect of exchange rate changes on cash                (80)         (90)
                                                     -----       ------
Net (decrease) increase in cash                        405       10,071
 
Cash at beginning of period                         17,560       35,506
                                                   -------      -------
Cash at end of period                              $17,965      $45,577
                                                   =======      =======
 

                                       5
<PAGE>
 
                                 CBT GROUP PLC

             NOTES TO CONDENSED CONSOLIDATED FINANCIAL STATEMENTS


NOTE 1  INTERIM CONSOLIDATED FINANCIAL STATEMENTS

 These interim consolidated financial statements have been prepared in
 accordance with generally accepted accounting principles for interim financial
 information and with the instructions to Form 10-Q. Accordingly, they do not
 include all the information and footnotes required by generally accepted
 accounting principles for complete financial statements. In the opinion of
 management, all adjustments (consisting of normal recurring accruals),
 considered necessary for a fair presentation of financial position, results of
 operations and cash flows at the dates and for the periods presented have been
 included. The interim financial information herein is not necessarily
 indicative of results for any future period.


NOTE 2  ACQUISITION OF THE FOREFRONT GROUP, INC

 On May 29, 1998, CBT Group PLC ("CBT," or the "Company") completed the
 acquisition of The ForeFront Group, Inc ("ForeFront"). The Company issued
 approximately 2.2 million ADSs in connection with the acquisition and assumed
 options, warrants and other rights to acquire ForeFront common stock that can
 be exercised for approximately 1.0 million ADSs. The transaction is being
 accounted for as a "pooling of interests" in accordance with U.S. generally
 accepted accounting principles.

 The results of operations of the previously separate companies from the
 beginning of the fiscal year to the end of the interim period nearest 
 May 29, 1998 are as follows:

 -----------------------------------------------------------------------
 Six Months Ended
 -----------------------------------------------------------------------
 June 30, 1998
 -----------------------------------------------------------------------
                                    CBT        ForeFront       Combined
                                    ---        ---------       --------
 -----------------------------------------------------------------------
 (dollars in thousands)                                    
 -----------------------------------------------------------------------
 Revenue                          $72,677       $12,104        $84,781
 -----------------------------------------------------------------------
 Net Income                       $14,497       $(3,056)       $11,441
 -----------------------------------------------------------------------
 Change in Shareholders Equity   $132,041        $5,144       $137,185
 -----------------------------------------------------------------------

 CBT eliminates all intercompany transactions on consolidation. There were no
 intercompanmy transactions between the company and ForeFront.

 Reconciliation of revenue and earnings previously reported by CBT, based on 
 CBT's separate results before restating for the ForeFront pooling, to the 
 combined amounts currently presented in the condensed financial statements and 
 notes to the condensed financial statements are as follows:

            ------------------------------------------------------------------
               Three Months Ended                 Six Months Ended
            ------------------------------------------------------------------
                 June 30, 1997                     June 30, 1997
            ------------------------------------------------------------------
             CBT     ForeFront    Combined        CBT     ForeFront   Combined 
            ------------------------------------------------------------------
                 (dollars in thousands)             (dollars in thousands) 
            -------------------------------------------------------------------
                                             
 ------------------------------------------------------------------------------
 Revenue      $25,589   $4,166     $29,755        $48,164    $8,318    $56,482
 ------------------------------------------------------------------------------
 Net Income    $4,627  $(2,406)     $2,221         $7,563   $(3,793)    $3,770
 ------------------------------------------------------------------------------

NOTE 3  SHARE SPLIT

 On March 9, 1998 the Company effected a two-for-one split of its issued and
 outstanding ADSs.  Subsequent thereto, the Company's shareholders approved a
 proposal at the Company's 1998 Annual General Meeting to subdivide each of the
 Ordinary Shares of IR37.5p into four Ordinary Shares of IR9.375p (the "Ordinary
 Share Split"). As a consequence of the Ordinary Share Split, effective May 22,
 1998 each ADS represents and is exchangeable for one Ordinary Share (the "Ratio
 Change"). Aside from the Ratio Change, the Ordinary Share Split had no effect
 on the ADSs and had no effect on the number of ADSs outstanding.


NOTE 4  CHANGES IN ACCOUNTING PRINCIPLES

 Effective January 1, 1998, the Company adopted Statement of Financial
 Accounting Standards No. 130, "Reporting Comprehensive Income."  This Statement
 requires all items recognized under accounting standards as components of
 comprehensive earnings be reported in an annual financial statement that is
 displayed with the same prominence as other financial statements.  This
 Statement also requires that an entity classify items of other comprehensive
 earnings by their nature in an annual financial statement.  For example, other
 comprehensive income may include foreign currency translation adjustments,
 minimum pension liability adjustments, and other unrealized gains and losses on
 marketable securities classified as available-for-sale.  Annual financial
 statements for prior periods will be reclassified, as required.

                                       6
<PAGE>
 
 The Company's total comprehensive earnings were as follows:

                                                        Six months ended
                                                            June 30,
                                                     1997              1998
                                                  -----------       -----------
(dollars in thousands)                            (Unaudited)       (Unaudited)
                             
Net Income                                          $3,770            $11,441
Other Comprehensive Income                            (123)              (122)
                                                    ------            -------
                             
Total Comprehensive Income                           3,647             11,319
                                                    ======            =======




                                       7
<PAGE>
 
                                   SIGNATURE



Pursuant to the requirements of the Securities Exchange Act of 1934, Registrant
has duly caused this report to be signed on its behalf by the undersigned
thereunto duly authorized.


                                CBT GROUP PLC

Date: April 6, 1998             By:  /s/ William G. McCabe   
                                     ----------------------
                                     William G. McCabe 
                                     Chairman of the Board

Date: April 6, 1998             By:  /s/ Gregory M. Priest
                                     ----------------------
                                     Gregory M. Priest
                                     Chief Executive Officer and President




                                       8