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                                                         Exhibit 10(iii)A(26)(a)
                                                  


                       NATIONAL SERVICE INDUSTRIES, INC.

                  NONEMPLOYEE DIRECTOR DEFERRED STOCK UNIT PLAN




1.   Purpose

     1.1 The National Service  Industries,  Inc.  Nonemployee  Director Deferred
Stock Unit Plan is  intended to  increase  the  alignment  of the  interests  of
eligible  members  of the  Board  with  the  interests  of  stockholders  of the
Corporation  by increasing  their  incentive to contribute to the success of the
Corporation's  business  through the grant of Deferred Stock Units, on the terms
and conditions set forth herein.

2.  Definitions

     2.1 When used in this Plan, unless the context otherwise requires:

          (a)  "Annual Fee" shall mean the annual fee payable,  in cash or under
               this Plan, to an Eligible Director for service on the Board.

          (b)  "Board" shall mean the Board of Directors of the Corporation.

          (c)  "Chairman  Fee"  shall mean the fee,  if any,  payable in cash or
               under  this  Plan to an  Eligible  Director  for  service  as the
               Chairman of a committee of the Board.

          (d)  "Change of Control" shall mean:

                    The  acquisition  (other than from the  Corporation)  by any
               "Person"  (as the term  person is used for  purposes  of Sections
               13(d) or  14(d)  of the  Exchange  Act) of  beneficial  ownership
               (within the meaning of Rule 13d-3  promulgated under the Exchange
               Act) of twenty percent (20%) or more of the combined voting power
               of the Corporation's then outstanding voting securities; or

                    The  individuals  who, as of the Effective Date, are members
               of the Board  (the  "Incumbent  Board")  cease for any  reason to
               constitute at least two-thirds of the Board;  provided,  however,
               that  if  the  election,   or  nomination  for  election  by  the
               Corporation's stockholders, of any new director was approved by a
               vote of at least  two-thirds  of the  Incumbent  Board,  such new
               director  shall,  for purposes of this Plan,  be  considered as a
               member of the Incumbent Board; or


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Exhibit 10(iii)A(26)(a)
 

                    Approval by  stockholders of the Corporation of (1) a merger
               or consolidation involving the Corporation if the stockholders of
               the Corporation,  immediately before such merger or consolidation
               do  not,  as a  result  of such  merger  or  consolidation,  own,
               directly or  indirectly,  more than seventy  percent (70%) of the
               combined voting power of the then outstanding  voting  securities
               of the corporation resulting from such merger or consolidation in
               substantially  the  same  proportion  as their  ownership  of the
               combined voting power of the voting securities of the Corporation
               outstanding  immediately before such merger or consolidation,  or
               (2) a complete  liquidation or dissolution of the  Corporation or
               an  agreement  for  the  sale  or  other  disposition  of  all or
               substantially all of the assets of the Corporation.

                    Notwithstanding the foregoing, a Change in Control shall not
               be deemed to occur  pursuant  to  paragraph  (i)  solely  because
               twenty percent (20%) or more of the combined  voting power of the
               Corporation's  then  outstanding  securities is acquired by (i) a
               trustee or other fiduciary  holding  securities under one or more
               employee  benefit plans  maintained by the  Corporation or any of
               its  subsidiaries,  or (ii) any  corporation  which,  immediately
               prior to such acquisition, is owned directly or indirectly by the
               stockholders  of the  Corporation in the same proportion as their
               ownership of stock in the Corporation  immediately  prior to such
               acquisition.

          (e)  "Committee"  shall mean the  Executive  Resource  and  Nominating
               Committee  of  the  Board  or  such  other  committee  as  may be
               designated by the Board.

          (f)  "Corporation" shall mean National Service Industries, Inc.

          (g)  "Date of Grant" shall mean the date on which Deferred Stock Units
               are granted pursuant to Section 5.1.

          (h)  "Deferred  Stock Units"  shall mean the units issued  pursuant to
               Section 5.1 hereof.

          (i)  "Effective Date" shall mean June 1, 1996, the date when this Plan
               shall go into effect.

          (j)  "Eligible  Director"  shall mean each  member of the Board who is
               not at the time of  reference an employee of the  Corporation  or
               any Subsidiary.


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                                                         Exhibit 10(iii)A(26)(a)


          (k)  "Exchange Act" shall mean the Securities Exchange Act of 1934, as
               amended, and the rules and regulations promulgated thereunder.

          (l)  "Fair  Market  Value"  shall mean the average of the high and low
               sales  prices  of a share of Stock  as  reported  on the New York
               Stock  Exchange  Composite  Tape on the  five (5)  trading  dates
               immediately  preceding  the date for  which  such  value is being
               determined.

          (m)  "Optional  Amount"  shall mean the amount  elected by an Eligible
               Director for any year during the term hereof  pursuant to Section
               5.2 hereof.

          (n)  "Plan"  shall  mean  the  National   Service   Industries,   Inc.
               Nonemployee  Director  Deferred Stock Unit Plan, as such Plan may
               be amended from time to time.

          (o)  "Required Amount" shall mean one-fourth of the Annual Fee.

          (p)  "Stock" shall mean the Common Stock of the Corporation.

          (q)  "Subsidiary"  shall mean any  corporation  more than 50% of whose
               stock having general voting power is owned by the  Corporation or
               by a Subsidiary of the Corporation.

3.   Administration

     3.1 The Plan shall be administered by the Committee.

     3.2 The Committee may take such rules and establish such procedures for the
administration  of the Plan as it deems  appropriate to carry out the purpose of
the Plan,  provided that the Committee  shall have no discretion with respect to
the  grantee,   amount,  price  or  timing  of  any  Deferred  Stock  Unit.  The
interpretation  and  application  of the Plan or of any rule or  procedure,  any
other matter relating to or necessary to the  administration  of the Plan, shall
be determined by the Committee,  and any such  determination  shall be final and
binding on all persons. Deferred Stock Units shall be evidenced by agreements in
such form as shall be determined  from time to time by the  Committee,  provided
that the terms and conditions of each such agreement are not  inconsistent  with
this Plan.

4.   Capital Adjustments

     4.1 In the event of a reorganization,  recapitalization, stock split, stock
dividend,  combination of shares,  merger,  consolidation or a similar corporate
transaction,  the  number or class of shares of Stock  represented  by  Deferred
Stock Units granted hereunder shall be  proportionately  adjusted to reflect any
such transaction.


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Exhibit 10(iii)A(26)(a)



5.   Deferred Stock Units

     5.1 Quarterly Grant. The Corporation shall establish a bookkeeping  account
for each Eligible Director. On the first of each September, December, March, and
June on or after the Effective  Date and prior to the  termination  of this Plan
(subject  to Section  6.1  below),  the  bookkeeping  account  of each  Eligible
Director shall automatically be credited with the number of Deferred Stock Units
(rounded to the nearest  hundredth)  equal to the sum of (a)  one-fourth  of the
Required Amount plus (b) one-fourth of the Optional  Amount,  if any, divided by
(c) the Fair Market Value.

     5.2 Election of Optional Amount.  Each Eligible  Director shall be entitled
to elect,  with  respect to each year  during the term of this Plan  (subject to
Section 6.1  below),  such  portion of the Annual Fee in excess of the  Required
Amount and such portion of the Chairman Fee, if  applicable,  which the Eligible
Director  desires to be credited in Deferred Stock Units under Section 5.1 above
rather than paid in cash.  Such election  shall be made and  submitted  prior to
each  such  year on such  form as shall be  determined  from time to time by the
Committee;  provided,  however,  that the  election  for the portion of the 1996
calendar  year that this Plan is in effect  shall be made prior to  September 1,
1996 and shall be effective for the remainder of the calendar year commencing on
that date.

     5.3 Terms and Conditions of Deferred Stock Units.

          (a) The  Deferred  Stock  Units  shall  become  nonforfeitable  on the
earliest to occur of (i) the first  anniversary  of the Date of Grant,  (ii) the
Eligible  Director's  death,  disability or termination of service as a director
upon completion of the last term of office to which such director was elected or
(iii) the occurrence of a Change of Control.  If an Eligible Director  otherwise
terminates  service as a director of the  Corporation,  any Deferred Stock Units
that are  forfeitable  shall be forfeited as of the date of such  termination of
service.

          (b) As of each  dividend  payment  date  declared  with respect to the
Stock,  the  Corporation  shall credit to each  bookkeeping  account a number of
additional Deferred Stock Units equal to (i) the product of (x) the dividend per
share of Stock  payable  on such  dividend  payment  date and (y) the  number of
Deferred  Stock Units  credited to such  account as of the  applicable  dividend
record date  divided by (ii) the Fair  Market  Value of a share of Stock on such
dividend payment date.

          (c) Upon the  termination  of  service  of an  Eligible  Director  the
Eligible  Director shall receive a lump sum cash payment equal to the product of
(i) the Fair Market Value of a share of Stock on the date of such termination of
service and (ii) the number of nonforfeitable Deferred Stock Units then credited
to such Eligible Director's account.  Notwithstanding the foregoing, an Eligible
Director  may elect to  receive  the  distribution  with  respect  to his or her
account in five annual installments  commencing as soon as practicable following
the Eligible  Director's  termination  of service,  in which event the amount of
each installment shall be determined based upon the Fair Market Value of a share
of Stock as of the date preceding the date such installment payment is made. Any


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                                                         Exhibit 10(iii)A(26)(a)



such election may be made or changed at any time without  limitation,  provided,
however,  that any election (and any modification or revocation of any election)
shall not be given  effect  unless made at least two years prior to the Eligible
Director's termination of service.

          (d) The holder of  Deferred  Stock Units shall have none of the rights
of a stockholder of the Corporation. The Corporation's obligation hereunder with
respect to Deferred Stock Units shall be an unsecured  promise to pay the amount
described in paragraph (c) above at the times described therein.

6.   Term of Plan

     6.1 The Plan shall  remain in effect  until all  Deferred  Stock Units have
been paid under the terms of the Plan, provided that no Deferred Stock Units may
be granted on or after the tenth anniversary of the Effective Date.

7.   Amendment; Termination

     7.1 The Board may at any time and from time to time alter, amend,  suspend,
or  terminate  the  Plan in  whole  or in  part;  provided,  however,  that  the
provisions  of Article 5 shall not be amended more than every six months,  other
than to comport with changes in the Internal  Revenue Code of 1986,  as amended,
the  Employee   Retirement  Income  Security  Act,  as  amended,  or  the  rules
thereunder.  The termination or any  modification or amendment of the Plan shall
not,  without the consent of a director,  affect his or her rights under a grant
of Deferred Stock Units.

8.   Miscellaneous

     8.1 Deferred  Stock Units  granted  hereunder  shall not be  assignable  or
transferable  by the  director  except  by will or by the  laws of  descent  and
distribution.

     8.2 Nothing in the Plan shall be construed as conferring any right upon any
director to continue as a member of the Board.

     8.3 The Plan and all rights hereunder shall be construed in accordance with
and governed by the laws of the State of Delaware.

     8.4 The Corporation  shall have the right to require,  prior to any payment
hereunder,  payment by the recipient of any federal, state, local or other taxes
which may be required to be withheld  or paid in  connection  with such  payment
hereunder.