<PAGE>   1
                                  UNITED STATES
                       SECURITIES AND EXCHANGE COMMISSION

                             Washington, D.C. 20549

                                    FORM 10-K

                     ANNUAL REPORT UNDER SECTION 13 OR 15(d)
                     OF THE SECURITIES EXCHANGE ACT OF 1934

     For the Fiscal Year Ended Dec. 31, 1996 Commission File Number 0-14773

                         NATIONAL BANCSHARES CORPORATION

                Ohio                       34-1518564
       State of incorporation              I.R.S. Employer
                                           Identification No.

                  112 West Market Street, Orrville, Ohio 44667
                     Address of principal executive offices

Registrant's telephone number: (330) 682-1010

Securities registered pursuant to Section 12(b) of the Act:  None

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

                         Common Stock, $10.00 Par Value
                                 Title of Class

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 _____.

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

State the aggregate market value of the voting stock held by non-affiliates of
the registrant as of March 4, 1997: $42,036,561.

Indicate the number of shares outstanding of each of the registrant's classes of
common stock, as of March 4, 1997.

                   Common Stock, $10.00 Par Value: 1,143,852

Documents Incorporated by Reference:

- Portions of the registrant's Proxy Statement dated March 27,1997 and
previously filed March 20, 1997, are incorporated by reference into Part III. 
- Portions of the registrant's Annual Report to Shareholders, December 31, 1996
are incorporated by reference in Parts I, II, IV. 


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<PAGE>   2



Form 10-K Cross Reference Index                                        Page

  Part I
    Item 1 - Business
      Description of Business                                          4
      Financial Ratios - Note 1                                        A23
      Daily Average Balance Sheets, Interest and Rates - Note 1        A22
      Volume and Rate Variance Analysis                                5
      Rate Sensitivity Analysis                                        6
      Investment Portfolio                                             7
      Loan Portfolio                                                   8
      Summary of Loan Loss Experience                                  9
      Deposits                                                         10
    Item 2 - Properties                                                4
    Item 3 - Legal Proceedings                                         4
    Item 4 - Submission of Matters to a Vote of Security Holders  - None

  Part II
    Item 5 - Market for the Registrant's Common Equity
             and Related Stockholder Matters - Note 1                  A9
    Item 6 - Selected Financial Data - Note 1                          A1
    Item 7 - Management's Discussion and Analysis of Financial
             Condition and Results of Operation - Note 1               A2-8
    Item 8 - Financial Statements - Note 1                             A10-21
    Item 9 - Changes in and Disagreements with Accountants on
             Accounting and Financial Disclosure - None

  Part III
    Item 10- Directors of the Registrant - Note 2                      B3
             Executive Officers of the Registrant                      4
    Item 11- Executive Compensation - Note 2                           B5
    Item 12- Security Ownership of Certain Beneficial
             Owners and Management - Note 2                            B3
    Item 13- Certain Relationships and Related Transactions Note 2     B7

  Part IV
    Item 14- Exhibits, Financial Statement Schedules and Reports on Form 8-K
      Report of Deloitte & Touche L.L.P., Independent Auditors         A21
      Financial Statements: - Note 1
        Consolidated Balance Sheets as of December 31,
          1996 and 1995                                                A10
        Consolidated Statements of Income for the Years Ended
          December 31, 1996, 1995 and 1994                             A11
        Consolidated Statements of Cash Flows for the Years
          Ended December 31, 1996, 1995 and 1994                       A13
        Consolidated Statements of Changes in Stockholders'
          Equity for the Years Ended December 31, 1996,
          1995 and 1994                                                A12
        Notes to Financial Statements - Note 1                         A14-21
      Reports on Form 8-K filed in fourth quarter of 1996: None
      Exhibit Table                                                    12
  Signatures                                                           11

Appendix A - National Bancshares 1996 Annual Report to                 A
                 Shareholders

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<PAGE>   3


Note 1 - Incorporated by reference from the registrant's Annual Report to
     Shareholders for the year ended December 31, 1996 -- Appendix A

Note 2 - Incorporated by reference from the registrant's proxy
     statement dated March 27, 1997  previously filed with the SEC on 
     March 20, 1997









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<PAGE>   4



Item 1 - Business:

National Bancshares Corporation (the "Company"), incorporated in 1985, is a one
bank holding company for First National Bank, Orrville, Ohio (the "Bank"). The
formation was approved by shareholders on April 24, 1986 and consummated on June
2, 1986. The Bank offers a full line of services usually found in any commercial
bank operation, including checking accounts, savings accounts, certificates of
deposit, personal loans, loans to business and industry, installment loans,
safety deposit boxes and credit cards. The Bank does not have trust powers and,
therefore, does not offer trust services. The Bank operates nine full service
offices and one limited service office in a market area comprising most of Wayne
County, portions of western Stark County, northeastern Holmes County and
southern Medina County. There are approximately 17 other banking and thrift
organizations in the immediate market area. No major elimination of services
presently offered is anticipated in the immediate future.

The Bank is a member of the Federal Reserve System and its deposits are insured
by the Federal Deposit Insurance Corporation. It is subject to supervision,
examination and regulation by the Comptroller of the Currency. The Company is
also subject to supervision, examination and regulation by the Federal Reserve
System. Management is not currently aware of any regulatory recommendations
which if were to be implemented would have a material effect on the registrant.

Item 2 - Properties:

The headquarters of the Company and the Bank are located in Orrville, Ohio. The
Bank has a total of ten banking office buildings which are located in Orrville,
Dalton, Kidron, Smithville, Mt. Eaton, Apple Creek, Lodi and Seville, Ohio. All
buildings are owned by the Bank with the exception of the Seville Office which
is a leased facility.

Item 3 - Legal Proceedings

There were no legal proceedings other than ordinary routine litigation
incidental to business during 1996.

Item 10 - Executive Officers

The Executive Officers of the Company are as follows:

Name                       Age      Position
Charles J. Dolezal         44       President
                                    President of First National Bank

Michael D. Hofstetter      44       Sr. Vice President & Secretary-Treasurer
                                    Sr. Vice President & Controller of
                                    First National Bank

There is no family relationship between any of the above executive officers. Mr.
Dolezal has been an executive officer of the Company since its formation in 1986
and the Bank during the past 5 years. Mr. Hofstetter was appointed Sr. Vice
President and Secretary-Treasurer of the Company on January 1, 1990 and has been
an executive officer of the Bank during the past 5 years. Mr. Hofstetter has
tendered his resignation which will be effective in the second quarter of 1997.






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VOLUME AND RATE VARIANCE ANALYSIS

The following table represents a summary analysis of changes in interest income,
interest expense and the resulting net interest income on a tax equivalent basis
for the periods presented each, as compared with the preceding period. Volume is
based on daily average balances.

<TABLE>
<CAPTION>
(Dollars in thousands)                  1996 versus 1995                  1995 versus 1994
                                      Increase (Decreases)              Increase (Decreases)
                                       Due to Changes In                 Due to Changes In
                                -------------------------------    ------------------------------
                                                          Net                               Net
                                     Volume      Rate   Change         Volume      Rate   Change
                                -------------------------------    ------------------------------
<S>                                  <C>       <C>      <C>               <C>       <C>     <C> 
Interest Income
 Investment securities:
  Taxable                             ($591)    ($135)   ($726)           $61       $65     $126
  Nontaxable                            (41)       (4)     (45)           (20)      (24)     (44)
  (tax equivalent basis)*
 Federal funds sold                     (15)      (47)     (62)            91       135      226
 Loans (including
  nonaccrual loans)                   1,090      (154)     936            823       700    1,523
                                -------------------------------    ------------------------------

   Total interest Income
   (tax equivalent basis)*             $443     ($340)    $103           $955      $876   $1,831
                                ===============================    ==============================


Interest Expense
 Deposits
  Interest bearing checking            ($32)     ($42)    ($74)           $61       $86     $147
  Savings                                11         6       17            (74)        1      (73)
  Time, $100,000
   and over                              27        44       71             90       107      197
  Time, other                           194         3      197            236       413      649
 Other funds purchased                 (106)       (7)    (113)            84        63      147
                                -------------------------------    ------------------------------

   Total interest
    expense                             $94        $4      $98           $398      $669   $1,067
                                ===============================    ==============================


Changes in net
 interest income (tax
 equivalent basis)*                    $349     ($344)      $5           $558      $206     $764
                                ===============================    ==============================
<FN>

* Tax equivalence based on highest statutory tax rates of 34%.
</TABLE>




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RATE SENSITIVITY ANALYSIS

The following table summarizes the repricing opportunities of interest bearing
assets and liabilities

Gap Report
December 31, 1996
(Millions of dollars)
<TABLE>
<CAPTION>

                                  3 Months          6 Months          12 Months         1-5 Years           5+ Years
                               Period   Accum.   Period   Accum.   Period   Accum.   Period   Accum.     Period   Accum.

Rate sensitive assets:

<S>                             <C>      <C>       <C>     <C>       <C>     <C>       <C>     <C>         <C>     <C>  
 Fed funds sold                 $10.8    $10.8     $0.0    $10.8     $0.0    $10.8     $0.0    $10.8       $0.0    $10.8
 Securities                       3.0      3.0      2.8      5.8      6.0     11.8     36.6     48.4       28.8     77.2
 Net loans                       24.1     24.1     12.4     36.5     15.7     52.2     21.2     73.4        4.7     78.1
                             --------------------------------------------------------------------------------------------
TOTAL                           $37.9    $37.9    $15.2    $53.1    $21.7    $74.8    $57.8   $132.6      $33.5   $166.1
                             ============================================================================================

Rate sensitive
 liabilities:
  Checking (1)                  $30.7    $30.7     $0.0    $30.7     $0.0    $30.7     $0.0    $30.7       $0.0    $30.7
  Savings (2)                     0.0      0.0      0.0      0.0      0.0      0.0     42.8     42.8        0.0     42.8
  Time                           18.8     18.8      8.7     27.5      9.4     36.9     14.1     51.0        0.0     51.0
  Money market borrow             4.0      4.0      0.0      4.0      0.0      4.0      0.0      4.0        0.0      4.0
  TT&L note account               0.9      0.9      0.0      0.9      0.0      0.9      0.0      0.9        0.0      0.9
                             --------------------------------------------------------------------------------------------
TOTAL                           $54.4    $54.4     $8.7    $63.1     $9.4    $72.5    $56.9   $129.4       $0.0   $129.4
                             ============================================================================================


Rate sensitivity gap           -$16.5   -$16.5     $6.5   -$10.0    $12.3     $2.3     $0.9     $3.2      $33.5    $36.7

Gap percentage                    70%      70%     175%      84%     231%     103%     102%     102%     NA         128%

Gap/total assets                  -9%      -9%       4%      -6%       7%       1%       0%       2%        19%      20%

Gap/capital                      -67%     -67%      26%     -40%      50%       9%       4%      13%       135%     148%
<FN>

(1) Checking includes NOW and MMDA

(2) Savings includes passbook and statement savings which do not have a preset
repricing date and have been included in the 1-5 years due to the relative
interest rate insensitivity.
</TABLE>

The potential impact on the net interest margin from modestly rising interest
would be relatively insignificant due to the short duration of mismatch within
the first 12 months. If interest rates were to immediately increase by 200 basis
points, this could cause an increase interest expense greater than interest
income. The potential impact would equate to lowering the current net interest
income by approximately 1.9% over the first 12 months.





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INVESTMENT PORTFOLIO

The carrying amounts and distribution of the Company's investment securities
held are summarized in the Annual Report to Shareholders (Appendix A, Page 15,
Note 3). The carrying amount, maturities and approximate weighted average yields
(on a tax equivalent basis) at December 31, 1996 are as follows:

INVESTMENT PORTFOLIO
December 31, 1996
(Dollars in thousands)
<TABLE>
<CAPTION>

                                     Total                 0 to 1 Year             1 to 5 Years           5 Years and Over
                              Amount       Yield       Amount       Yield       Amount       Yield      Amount       Yield

<S>                        <C>              <C>    <C>              <C>     <C>              <C>    <C>               <C> 
US Treasury                $ 15,166         6.9%   $   6,031        7.3%    $   8,096        6.5%   $   1,039         8.5%
US Agencies                  21,937         6.7%         334        7.2%        7,606        6.0%      13,997         7.1%
State & political
 subdivisions                16,923         9.1%         220        9.0%        7,851        8.8%       8,852         9.4%
Other securities             23,240         6.9%       5,325        7.4%       13,003        7.1%       4,912         5.9%
                        ---------------------------------------------------------------------------------------------------
TOTAL                      $ 77,266         7.4%    $ 11,910        7.4%     $ 36,556        7.2%    $ 28,800         7.7%
                        ===================================================================================================
</TABLE>

$2.5 million of investment securities have a remaining maturity more than 10
years. There was no single issuer of securities where the total book value of
such securities exceeded 10% of shareholders' equity except for US government
obligations.






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LOAN PORTFOLIO

The detail of the loan portfolio balances are included in the Annual Report to
Shareholders (Appendix A, Page 16, Note 4).

MATURITIES AND SENSITIVITIES OF LOANS TO CHANGES IN INTEREST RATES

The following are approximate maturities and sensitivity to changes in interest
rates of certain loans exclusive of real estate mortgages and consumer loans as
of December 31, 1996.
<TABLE>
<CAPTION>

Types of Loans                            0 to 1 Year     1 to 5 Years      5 and Over Years   Total
<S>                                          <C>             <C>                    <C>        <C>    
(Dollars in Thousands)
Commercial                                   $9,929          $1,385               $231        $11,545
Real Estate Construction                       $761            $424               $278         $1,463

Above loans due beyond 1 year with:

Predetermined interest rates                                                                     $719
Adjustable interest rates                                                                      $1,599

</TABLE>

NONACCRUAL AND PAST DUE LOANS

Generally, recognition of interest income is discontinued where reasonable doubt
exists as to the collectability of the interest. Income from nonaccrual loans is
recorded when received. The difference between interest income recognized on
such loans and income that would have been recognized at original contractual
rates is immaterial. The bank generally places loans on a non-accrual status
when a default of principal or interest has existed for 90 days or more. The
bank generally does not renegotiate loans due to deterioration in the financial
position of the borrower. The amounts of renegotiated loans are not considered
material.

(Dollars in Thousands)                 12/31/96    12/31/95
90 Days Past Due and Accruing              $458        $138
Nonaccruing Loans                           $85         $68


POTENTIAL LOAN PROBLEMS

Management reviews the loan portfolio for potential loan problems on a monthly
basis. The following loans were classified by management and include in the
above nonaccrual and past due loan totals. The amount shown below is the
outstanding loan balance which has not been reduced by collateral values.

(Dollars in Thousands)        12/31/96      12/31/95
Loss                                $0            $0
Doubtful                            95            80
Substandard                        930           623
OAEM                               742         1,036
Watch                                0             9
                           ------------   -----------
Total                           $1,767        $1,748
                           ============   ===========



LOAN CONCENTRATIONS

Due to the nature of our market area, it is management's opinion that there are
no significant loan concentrations of 10% of total loans to borrowers engaged in
similar activities other than noted in the loan categories disclosed in the
Annual Report to Shareholders (Appendix A, Page 16, Note 4).




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SUMMARY OF LOAN LOSS EXPERIENCE

The determination of the balance of the allowance for loan losses historically
has been based on an overall analysis of the loan portfolio and reflects an
amount, which, in management's judgment, is adequate to provide for potential
loan losses. This analysis considers, among other things, the Company's loan
loss experience, present and potential risks of the loan portfolio and general
economic conditions. In addition, management considers the examinations of the
loan portfolio by federal regulatory agencies and internal reviews and
evaluations. The Company's allocation of the allowance for loan losses by
category represents only an estimate for each category of loans based upon a
detailed review of the loan portfolio by management.

Transactions in the allowance for loan losses are maintained by three major loan
categories and the summary of such transactions for periods indicated follows:
<TABLE>
<CAPTION>

CHANGES IN ALLOWANCE
FOR LOAN LOSSES
(Dollars in Thousands)                     1996           1995

<S>                                           <C>               <C> 
Balance at the beginning of period            $1,046            $891
Loans charged off:
 Commercial & industrial                          77               3
 Real estate                                       5               0
 Consumer                                         60              38
                                      -------------------------------
Total loans charged off                          142              41
                                      -------------------------------

Recoveries of loans charged off:
 Commercial & industrial                          43               0
 Real estate                                       0               3
 Consumer                                         24              13
                                      -------------------------------
Total recoveries                                  67              16
                                      -------------------------------
Net loans charged off                             75              25
                                      -------------------------------
Provision charged to
 operating expense                               180             180
                                      -------------------------------
Balance at end of period                      $1,151          $1,046
                                      ===============================

Net charge-offs to
 average loans                                  0.10            0.03
                                      ===============================

</TABLE>

<TABLE>
<CAPTION>

DISTRIBUTION OF ALLOWANCE FOR
LOAN LOSSES BY CATEGORY
(Dollars in thousands)                          December 31, 1996              December 31, 1995

                                                              % of                          % of
                                              Amount       Total Loans      Amount      Total Loans

<S>                                              <C>             <C>         <C>               <C>
Commercial & industrial                          $74             17%         $113              17%
Real estate construction                           0              2%            0               2%
Real estate mortgages                             18             67%           10              61%
Consumer loans                                    19             14%           20              20%
Unallocated                                     1040             N/A          903              N/A
                                      -------------------------------------------------------------
TOTAL                                         $1,151            100%       $1,046             100%
                                      =============================================================
</TABLE>






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DEPOSITS

The classification of average deposits and the average rate paid on such
deposits for periods ending December 31, 1996, 1995 and 1994 is included in
Analysis of Net Interest Earnings included in the Annual Report to Shareholders
( Appendix A, Page 22).

 A summary of maturities of time deposits of $100,000 or more is as follows.

<TABLE>
<CAPTION>
                                                       12/31/96             12/31/95

<S>                                          <C>                  <C>               
Three months or less                         $        9,514,277   $        9,629,509
Over 3 months through 6 months                          218,945              416,409
Over 6 months through 12 months                         809,918              100,000
Over 12 months                                        1,026,845              806,526
                                           ------------------------------------------
                                              $      11,569,985    $      10,952,444
                                           ==========================================
</TABLE>







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                                   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.

                         NATIONAL BANCSHARES CORPORATION

DATE:          3-18-97              /s/ Charles J. Dolezal
         -----------------         ------------------------
                                    Charles J. Dolezal, President

DATE:          3-18-97              /s/ Michael D. Hofstetter
         -----------------         ------------------------
                                    Michael D. Hofstetter, Secretary-Treasurer
                                    (Principal Financial Officer)

Pursuant to the requirements of the Securities Exchange Act of 1934, this report
has been signed by the following persons on behalf of the registrant and in the
capacities and on the dates indicated.

DATE:          3-18-97              /s/ Charles J. Dolezal
         -----------------         --------------------------------
                                    Charles J. Dolezal, Chairman

DATE:          3-18-97              /s/ James L. Gerber
         -----------------         --------------------------------
                                    James L. Gerber, Director

DATE:          3-18-97              /s/ James F. Woolley
         -----------------         --------------------------------
                                    James F. Woolley, Director

DATE:          3-18-97              /s/ John W. Kropf
         -----------------         --------------------------------
                                    John W. Kropf, Director

DATE:          3-18-97              /s/ John E. Sprunger
         -----------------         --------------------------------
                                    John E. Sprunger, Director

DATE:          3-18-97              /s/ Sara E. Balzarini
         -----------------         --------------------------------
                                    Sara E. Balzarini, Director




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<TABLE>
<CAPTION>

EXHIBIT INDEX

Exhibit No.                                                                     If incorporated by Reference,
Under Reg.          Form 10-K                                                   Documents with Which Exhibit
S-K, Item 601       Exhibit No.       Description of Exhibits                   was Previously Filed with SEC
-------------       -----------       -----------------------                   -----------------------------

<S>                 <C>               <C>                                       <C>                        
(3)(i)                                Amended Articles of Incorporation         Registration Statement S-4 filed
                                                                                3/31/86 File No. 33-03711

(3)(ii)                               Code of Regulations                       Registration Statement S-4 filed
                                                                                3/31/86 File No. 33-03711

(11)                A18               Computation of Earnings per Share         Incorporated by reference

(12)                A18               Computation of Ratios                     Incorporated by reference

(13)                A                 1996 Annual Report to Shareholders        

(21)                A1                Subsidiaries of the registrant            Incorporated by reference

(23)                                  Consent of Deloitte & Touche, L.L.P.

(27)                                  Financial Data Schedule

No other exhibits are required to be filed herewith pursuant to Item 601 of
Regulation S-K.
</TABLE>





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