<PAGE>   1
                                  UNITED STATES
                       SECURITIES AND EXCHANGE COMMISSION
                              Washington, DC 20549


                                    FORM 10-Q
                Quarterly report pursuant to section 13 or 15 (d)
                     of the Securities Exchange Act of 1934

FOR THE QUARTER ENDED JUNE 30, 2000              COMMISSION FILE NUMBER 0-13875


                               LANCER CORPORATION
             (Exact name of registrant as specified in its charter)

<TABLE>
<S>                                                           <C>
                TEXAS                                            74-1591073
   (State or other jurisdiction of                              (IRS employer
   incorporation or organization)                            identification no.)

6655 LANCER BLVD., SAN ANTONIO, TEXAS                               78219
(Address of principal executive offices)                         (Zip Code)
</TABLE>

       Registrant's telephone number, including area code: (210) 310-7000

Indicate by check mark whether the registrant (1) has filed all reports required
to be filed by Section 13 or 14(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
                                       ---     ---

Indicate the number of shares outstanding of each of the issuers of classes of
common stock, as of the latest practicable date.

<TABLE>
<CAPTION>
                   TITLE                                                 SHARES OUTSTANDING AS OF
                                                                              AUGUST 3, 2000
<S>                                                                      <C>
Common stock, par value $.01 per share                                          9,124,857
</TABLE>

<PAGE>   2

Part I - Financial Information
ITEM 1 - FINANCIAL STATEMENTS

                       LANCER CORPORATION AND SUBSIDIARIES
                           CONSOLIDATED BALANCE SHEETS

                    (Amounts in thousands, except share data)

<TABLE>
<CAPTION>
                                     ASSETS

                                                     June 30,  December 31,
                                                       2000       1999
                                                   ---------   -----------
                                                   (Unaudited)
<S>                                                <C>          <C>
Current assets:
  Cash                                             $     830    $   1,227
  Receivables:
    Trade accounts and notes                          20,400       17,483
    Other                                                559          537
                                                   ---------    ---------

                                                      20,959       18,020
    Less allowance for doubtful accounts                (397)        (414)
                                                   ---------    ---------
      Net receivables                                 20,562       17,606
                                                   ---------    ---------

  Inventories                                         38,887       36,166
  Prepaid expenses                                       703          465
  Income tax receivable                                   --        3,505
  Deferred tax asset                                      95          134
                                                   ---------    ---------

      Total current assets                            61,077       59,103
                                                   ---------    ---------

Property, plant and equipment, at cost:
  Land                                                 1,260        1,260
  Buildings                                           21,885       21,880
  Machinery and equipment                             20,838       20,531
  Tools and dies                                       9,879        9,025
  Leaseholds, office equipment and vehicles            9,852        8,941
  Assets in progress                                   2,317        1,821
                                                   ---------    ---------

                                                      66,031       63,458

  Less accumulated depreciation and amortization     (29,621)     (27,795)
                                                   ---------    ---------
    Net property, plant and equipment                 36,410       35,663
                                                   ---------    ---------

Long-term receivables ($766 and $746 due
    from officers, respectively)                       1,043        1,029
Long-term investments                                  2,874        3,053
Intangibles and other assets,
   at cost, less accumulated amortization              4,015        4,206
                                                   ---------    ---------

                                                   $ 105,419    $ 103,054
                                                   =========    =========
</TABLE>

          See accompanying notes to consolidated financial statements.

                                        2
<PAGE>   3

                       LANCER CORPORATION AND SUBSIDIARIES
                     CONSOLIDATED BALANCE SHEETS (CONTINUED)

                    (Amounts in thousands, except share data)

                      LIABILITIES AND SHAREHOLDERS' EQUITY

<TABLE>
<CAPTION>
                                                  June 30,    December 31,
                                                    2000         1999
                                                 ---------   -----------
                                                (Unaudited)
<S>                                              <C>              <C>
Current liabilities:
  Accounts payable                               $   9,592        9,119
  Current installments of long-term debt             4,447        5,083
  Line of credit with bank                          20,300       17,600
  Deferred licensing and maintenance fees              774          619
  Accrued expenses and other liabilities             4,586        4,091
  Taxes payable                                      2,055           --
                                                 ---------    ---------

    Total current liabilities                       41,754       36,512

Deferred tax liability                               2,596        3,102
Long-term debt, excluding current installments      11,971       13,922
Deferred licensing and maintenance fees              3,803        4,500
                                                 ---------    ---------

    Total liabilities                               60,124       58,036
                                                 ---------    ---------

Commitments and contingencies                           --           --

Minority interest                                      406          542

Shareholders' equity:
  Preferred stock, without par value
  5,000,000 shares authorized; none issued              --           --

  Common stock, $.01 par value:
   50,000,000 shares authorized; 9,124,857
   issued and outstanding                               91           91

  Additional paid-in capital                        11,933       11,933

  Accumulated other comprehensive loss              (2,524)      (1,816)

  Retained earnings                                 35,389       34,268
                                                 ---------    ---------

    Total shareholders' equity                      44,889       44,476
                                                 ---------    ---------

                                                 $ 105,419    $ 103,054
                                                 =========    =========
</TABLE>


          See accompanying notes to consolidated financial statements.

                                        3
<PAGE>   4

                       LANCER CORPORATION AND SUBSIDIARIES
                        CONSOLIDATED STATEMENTS OF INCOME
                                   (Unaudited)

                    (Amounts in thousands, except share data)

<TABLE>
<CAPTION>
                                            Three Months Ended          Six Months Ended
                                         June 30,       June 30,       June 30,      June 30,
                                           2000          1999           2000           1999
                                       -----------    -----------    -----------    -----------
<S>                                    <C>            <C>            <C>            <C>
Net sales                              $    31,551    $    38,072    $    59,280    $    74,300
Cost of sales                               23,395         30,498         44,887         58,658
                                       -----------    -----------    -----------    -----------
    Gross profit                             8,156          7,574         14,393         15,642

Selling, general and
   administrative expenses                   6,093          5,355         11,085         10,548
                                       -----------    -----------    -----------    -----------

    Operating income                         2,063          2,219          3,308          5,094
                                       -----------    -----------    -----------    -----------

Other (income) expense:
  Interest expense                             802            896          1,468          1,804
  (Earnings) loss from joint venture           (58)        (1,068)            33         (1,528)
  Minority interest                            (69)            --           (136)            --
  Other (income) expense, net                  (44)            73            (50)            (7)
                                       -----------    -----------    -----------    -----------
                                               631            (99)         1,315            269
                                       -----------    -----------    -----------    -----------

    Income before income taxes               1,432          2,318          1,993          4,825
                                       -----------    -----------    -----------    -----------

Income tax expense (benefit):
  Current                                    1,130            764          1,377          1,717
  Deferred                                    (504)           104           (505)           207
                                       -----------    -----------    -----------    -----------

                                               626            868            872          1,924
                                       -----------    -----------    -----------    -----------


    Net earnings                       $       806    $     1,450    $     1,121    $     2,901
                                       ===========    ===========    ===========    ===========

Common Shares and
  Equivalents Outstanding:
Basic                                    9,124,857      9,121,482      9,124,857      9,121,482
Diluted                                  9,263,726      9,283,841      9,283,900      9,313,484

Earnings Per Share:
Basic                                  $      0.09    $      0.16    $      0.12    $      0.32
Diluted                                $      0.09    $      0.16    $      0.12    $      0.31
</TABLE>


          See accompanying notes to consolidated financial statements.

                                        4
<PAGE>   5

                       LANCER CORPORATION AND SUBSIDIARIES
                      CONSOLIDATED STATEMENTS OF CASH FLOWS
                                   (Unaudited)

<TABLE>
<CAPTION>
                                                                     Six Months Ended
                                                                   June 30,   June 30,
                                                                    2000       1999
                                                                  --------   ---------
<S>                                                               <C>        <C>
Cash flow from operating activities:
     Net earnings                                                 $ 1,121    $ 2,901
     Adjustments to reconcile net earnings to net cash
        provided by (used in) operating activities
        Depreciation and amortization                               2,074      1,828
        Deferred licensing and maintenance fees                      (542)       167
        Deferred income taxes                                        (505)       250
        Gain on sale and disposal of assets                            (1)        (8)
        Minority interest                                            (136)        --
        Loss (earnings) from joint venture                             33     (1,528)
        Changes in assets and liabilities:
            Receivables                                            (3,436)    (3,095)
            Prepaid expenses                                         (238)      (150)
            Income taxes receivable                                 3,505        205
            Inventories                                            (3,055)     1,995
            Other assets                                             (138)      (329)
            Accounts payable                                          804        760
            Accrued expenses                                          546       (455)
            Income taxes payable                                    2,083        405
                                                                  -------    -------
     Net cash provided by operating activities                      2,115      2,946
                                                                  -------    -------

Cash flow from investing activities:
        Proceeds from sale of assets                                    2         12
        Acquisition of property, plant and equipment               (2,796)    (2,434)
        Acquisition of subsidiary company                              --     (1,718)
        Cash proceeds from long-term investments and affiliates       235        706
                                                                  -------    -------
     Net cash used in investing activities                         (2,559)    (3,434)
                                                                  -------    -------

Cash flow from financing activities:
        Net borrowings under line of credit agreements              2,700      1,800
        Retirement of long-term debt, net of proceeds              (2,536)    (1,109)
                                                                  -------    -------
     Net cash provided by financing activities                        164        691
                                                                  -------    -------
Effect of exchange rate changes on cash                              (117)      (185)
                                                                  -------    -------
Net (decrease) increase in cash                                      (397)        18
Cash at beginning of period                                         1,227      1,119
                                                                  -------    -------
Cash at end of period                                             $   830    $ 1,137
                                                                  =======    =======
</TABLE>


          See accompanying notes to consolidated financial statements.

                                        5
<PAGE>   6

                       LANCER CORPORATION AND SUBSIDIARIES
                   NOTES TO CONSOLIDATED FINANCIAL STATEMENTS


1.       BASIS OF PRESENTATION

All adjustments (consisting of normal recurring adjustments) have been made
which are necessary for a fair presentation of financial position and results of
operations. All intercompany balances and transactions have been eliminated in
consolidation. It is suggested that the consolidated financial statements be
read in conjunction with the consolidated financial statements and notes thereto
included in the December 31, 1999 Annual Report on Form 10-K.

Certain amounts in the consolidated financial statements for prior periods have
been reclassified to conform with the current year's presentation.

2.       INVENTORY COMPONENTS

Inventories are stated at the lower of cost or market on a first-in, first-out
basis (average cost as to raw materials and supplies) or market (net realizable
value). Inventory components are as follows (dollars in thousands):


<TABLE>
<CAPTION>
                            June 30, December 31,
                             2000      1999
                            -------  -----------
<S>                         <C>       <C>
Finished goods              $15,012   $14,662
Work in process              10,322    10,828
Raw material and supplies    13,553    10,676
                            -------   -------
                            $38,887   $36,166
                            =======   =======
</TABLE>

3.       EARNINGS PER SHARE

Basic earnings per share is calculated using the weighted average number of
common shares outstanding and diluted earnings per share is calculated assuming
the issuance of common shares for all potential dilutive common shares
outstanding during the reporting period. The dilutive effect of stock options
approximated 138,869 and 162,359 shares for the three months ended June 30, 2000
and 1999, and 159,043 and 192,002 shares for the six months ended June 30, 2000
and 1999, respectively.


                                        6
<PAGE>   7

                       LANCER CORPORATION AND SUBSIDIARIES
                   NOTES TO CONSOLIDATED FINANCIAL STATEMENTS


4.       COMPREHENSIVE INCOME

The following are the components of comprehensive income (amounts in thousands):

<TABLE>
<CAPTION>
                                                    Three Months Ended     Six Months Ended
                                                     June 30,  June 30,   June 30,   June 30,
                                                      2000      1999       2000       1999
                                                    --------   -------    -------    -------
<S>                                                 <C>        <C>        <C>        <C>
Net earnings                                        $   806    $ 1,450    $ 1,121    $ 2,901
Foreign currency gain (loss) arising
   during the period                                   (249)        31       (766)    (1,306)
Unrealized gain (loss) on investment (net of tax)       (19)       (12)        58        102
                                                    -------    -------    -------    -------
Comprehensive income                                $   538    $ 1,469    $   413    $ 1,697
                                                    =======    =======    =======    =======
</TABLE>

Accumulated other comprehensive loss on the accompanying consolidated balance
sheets includes foreign currency translation adjustments and unrealized gain
(loss) on investment.

5.       SEGMENT AND GEOGRAPHIC INFORMATION

The Company and its subsidiaries are engaged in the manufacture and distribution
of beverage dispensing equipment and related parts and components. The Company
manages its operations geographically. Sales are attributed to a region based on
the ordering location of the customer. (Amounts in thousands)

<TABLE>
<CAPTION>
                                      North        Latin
                                     America      America    Pacific      Brazil    Europe       Asia     Corporate     Total
                                    ---------     --------   --------    -------   -------     --------   ----------   -------
<S>                                 <C>          <C>        <C>          <C>       <C>         <C>        <C>         <C>
Three months ended June 30, 2000
  Total revenues                    $ 19,802     $ 2,238    $ 4,188       $ 288    $ 4,030     $ 1,005    $     -    $ 31,551
  Operating income (loss)              3,944         299        449          (3)       909         371     (3,906)      2,063

Three months ended June 30, 1999
  Total revenues                    $ 25,477     $ 3,177    $ 3,319       $ 481    $ 3,287     $ 2,331    $     -    $ 38,072
  Operating income (loss)              3,928         379        295        (149)       418         362     (3,014)      2,219

Six months ended June 30, 2000
  Total revenues                    $ 37,655     $ 3,909    $ 9,109       $ 862    $ 5,998     $ 1,747    $     -    $ 59,280
  Operating income (loss)              6,355         665      1,287          50      1,069         645     (6,763)      3,308

Six months ended June 30, 1999
  Total revenues                    $ 48,679     $ 6,986    $ 6,592       $ 825    $ 6,327     $ 4,891    $     -    $ 74,300
  Operating income (loss)              8,451         780        598        (553)     1,003         725     (5,910)      5,094
</TABLE>

All intercompany revenues are eliminated in computing revenues and operating
income. The corporate component of operating income represents corporate general
and administrative expenses.


                                        7
<PAGE>   8

                       LANCER CORPORATION AND SUBSIDIARIES

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

This document contains certain "forward-looking" statements as such term is
defined in the Private Securities Litigation Reform Act of 1995 and information
relating to the Company and its subsidiaries that are based on the beliefs of
the Company's management. When used in this report, the words "anticipate,"
"believe," "estimate," "expect," "forecast," "plan," and "intend" and words or
phrases of similar import, as they relate to the Company or its subsidiaries or
Company management, are intended to identify forward-looking statements. Such
statements reflect the current risks, uncertainties and assumptions which exist
or must be made as a result of certain factors including, without limitation,
competitive factors, general economic conditions, customer relations,
relationships with vendors, the interest rate environment, governmental
regulation and supervision, seasonality, distribution networks, product
introductions and acceptance, one-time events and other factors described herein
and in other filings made by the Company with the Securities and Exchange
Commission. Based upon changing conditions, should any one or more of these
risks or uncertainties materialize, or should any underlying assumptions prove
incorrect, actual results may vary materially from those described herein as
anticipated, believed, estimated, expected, forecast, planned or intended. The
Company does not intend to update these forward-looking statements.

RESULTS OF OPERATIONS

Comparison of the Three-Month Periods Ended June 30, 2000 and 1999

Net sales for the quarter ended June 30, 2000 were $31.6 million, down 17% from
net sales in the second quarter of 1999. Sales in the Company's North American
region declined 22%, primarily because of lower sales of frozen beverage
equipment. Revenue fell 30% in Latin America (excluding Brazil), and 57% in
Asia. Market conditions in the two regions remained unfavorable. Sales in the
Pacific region increased 26%, due largely to strong demand for beer equipment.

Gross margin in the second quarter of 2000 was 25.9%, up from 19.9% in the
second quarter of 1999. The improvement in margin was caused primarily by lower
sales of frozen beverage equipment. The Company buys the equipment from a joint
venture of which the Company owns 50%. The Company resells the dispensers and
earns a distribution profit, which is reflected in gross margin. The Company's
50% share of the manufacturing profit, after elimination of profit in ending
inventory, is included in other income. Better plant utilization and improved
manufacturing efficiencies also contributed to the margin gain.

Selling, general and administrative expenses for the second quarter of 2000 were
$6.1 million, compared to $5.4 million in the same period of 1999. The increase
was caused partially by new product development, and by the Company's ABS
distribution subsidiary in Chicago, which did not exist in the second quarter of
1999.

Interest expense in the second quarter of 2000 was $0.8 million, down from the
second quarter of 1999 primarily because of lower average borrowings. The
Company's earnings from its frozen beverage joint venture declined by $1.0
million in the 2000 period because of lower production levels at the joint
venture. The minority interest benefit of $0.1 million stems from the Company's
majority ownership position in Lancer Ice Link, LLC, and represents the minority
partner's share of the subsidiary's losses. Lancer Ice Link's operations are
consolidated with those of the Company. The effective tax rate was 43.7% in the
second quarter of 2000, compared to 37.4% in the second quarter of 1999. The
effective rate rose in 2000 primarily because a larger proportion of the
Company's earnings was in high tax rate jurisdictions, and because of
non-deductible expenses. Second quarter net income was $0.8 million in 2000,
versus $1.5 million in 1999.


                                        8
<PAGE>   9

Comparison of the Six-Month Periods Ended June 30, 2000 and 1999

Net sales for the first six months of 2000 were $59.3 million, down 20% from net
sales in the same period of 1999. Sales in the North America region declined
23%, primarily because of lower sales of frozen beverage dispensers. Revenue
fell 44% in Latin America (excluding Brazil) and 64% in Asia, as market
conditions remained unfavorable in the two regions. Revenue in the Pacific
region rose 38%, due largely to strong demand for beer equipment.

Gross margin in the first half of 2000 was 24.3%, compared to 21.1% in the first
half of 1999. The improvement in margin was caused primarily by lower sales of
frozen beverage equipment. The Company buys the equipment from a joint venture
of which the Company owns 50%. The Company resells the dispensers and earns a
distribution profit, which is reflected in gross margin. The Company's 50% share
of the manufacturing profit, after elimination of profit in ending inventory, is
included in other income.

Selling, general and administrative expenses were $11.1 million during the first
six months of 2000, compared to $10.5 million in the first half of 1999. The
increase was partially caused by new product development expenses, and by the
Company's ABS distribution subsidiary in Chicago, which did not exist in the
first half of 1999.

Interest expense in the first six months of 2000 was $1.5 million, down from
$1.8 million in the same period last year primarily because of lower average
borrowings. The Company's earnings from its frozen beverage joint venture
declined by $1.6 million in the first half of 2000 because of lower production
levels at the joint venture. The minority interest benefit stems from the
Company's majority ownership position in Lancer Ice Link, LLC, and represents
the minority partner's share of the subsidiary's losses. Lancer Ice Link's
operations are consolidated with those of the Company. The effective tax rate
was 43.8% in the first half of 2000, compared to 39.9% in the first half of
1999. The effective rate rose in 2000 primarily because a larger proportion of
the Company's earnings was earned in high tax rate jurisdictions, and because of
non-deductible expenses. Net income was $1.1 million in the first half of 2000,
versus $2.9 million in the same period of 1999.

Liquidity and Capital Resources

The Company's principal sources of liquidity are cash flows from operations and
amounts available under the Company's existing lines of credit. The Company has
met, and currently expects that it will continue to meet, substantially all of
its working capital and capital expenditure requirements, as well as its debt
service requirements, with funds provided by operations and borrowings under its
credit facilities. The Company is in compliance with, or has obtained waivers
of, the financial covenants contained in the credit agreement that governs the
Company's primary credit facilities.

Cash provided by operating activities was $2.1 million in the first six months
of 2000, compared to $2.9 million in the same period last year. The Company made
capital expenditures of $2.8 million in the first half of 2000, primarily for
production tooling and equipment.

Accounting Matters

The Company maintains a DISC in order to defer income taxes on its foreign
sales. The Company continues to evaluate the benefit of converting the DISC to a
Foreign Sales Corporation. At the time of such conversion, the Company will be
required to provide for federal income taxes on $2.4 million of undistributed
earnings of the DISC. See 1999 Form 10-K.

The Internal Revenue Service is examining the Company's U.S. income tax return
for 1995. Management does not believe that any significant adjustments will be
required as a result of this review.


                                        9
<PAGE>   10

In June 1998, the Financial Accounting Standards Board ("FASB") issued Statement
of Financial Accounting Standards ("SFAS") No. 133, "Accounting for Derivative
Instruments and Hedging Activities." The Statement provides guidance on
accounting and financial reporting for derivative instruments and hedging
activities. The Statement requires the recognition of all derivatives as either
assets or liabilities in the consolidated balance sheet, and the periodic
measurement of those instruments at fair value. The Company plans to adopt SFAS
No. 133 effective January 1, 2001. The Company anticipates having certain
derivative instruments, principally interest rate swap agreements, at the time
of adoption. The Company is currently analyzing and assessing the impact that
the adoption of SFAS No. 133 is expected to have on its consolidated results of
operations, cash flows and financial position.

ITEM 3 - QUANTITATIVE AND QUALITATIVE DISCLOSURES ABOUT MARKET RISK

There have been no significant changes in the Company's market risk factors
since December 31, 1999.

ITEM 4 - SUBMISSION OF MATTERS TO A VOTE OF SECURITY HOLDERS

At the annual meeting of shareholders of the Company held on May 18, 2000, the
shareholders elected eight members of the Board of Directors of the Company to
serve until the next annual meeting of the shareholders.

The vote for nominated directors was as follows:

<TABLE>
<CAPTION>
        Nominee                             For               Authority Withheld
        -------                          ---------            -------------------
<S>                                      <C>                  <C>
Walter J. Beigler                        8,054,678                 173,811
Jean M. Braley                           8,056,190                 172,299
Charles K. Clymer                        8,056,678                 171,811
Olivia F. Kirtley                        8,057,690                 170,799
Alfred A. Schroeder                      8,052,490                 175,999
George F. Schroeder                      8,041,990                 186,499
Micheal E. Smith                         8,056,178                 172,311
E.T. (Toby) Summers                      8,057,690                 170,799
</TABLE>

ITEM 6 - EXHIBITS AND REPORTS ON FORM 8-K

         (a)      Exhibits:

                  Exhibit No.       Description

                  27                Financial Data Schedule

         (b)      Reports on Form 8-K:

                  None


                                       10
<PAGE>   11

SIGNATURES

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.

LANCER CORPORATION
(REGISTRANT)



August 11, 2000                      By:  /s/ GEORGE F. SCHROEDER
                                          -----------------------
                                          George F. Schroeder
                                          President and CEO



August 11, 2000                      By:  /s/ MARK L. FREITAS
                                          -------------------
                                          Mark L. Freitas
                                          Vice President - Controller


                                       11
<PAGE>   12

                               INDEX TO EXHIBITS


<TABLE>
<CAPTION>
EXHIBIT
NUMBER                        DESCRIPTION
-------                       -----------
<S>                      <C>
 27                      Financial Data Schedule
</TABLE>