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                                                                       EXHIBIT 5



                          [Quarles & Brady letterhead]

                                 June 20, 1996


Plexus Corp.
55 Jewelers Park Drive
Neenah, Wisconsin  54957-0156

Gentlemen and Ladies:

     We are providing this opinion in connection with the Registration
Statement of Plexus Corp. (the "Company") on Form S-8 (the "Registration
Statement") filed under the Securities Act of 1933, as amended (the "Act"),
with respect to the proposed sale by the Company of up to 350,000 shares of
Common Stock, par value $.01 per share, of the Company (the "Shares") pursuant
to the Plexus Corp. Employee Stock Savings Plan (the "Plan").  We have
examined:  (i) the Registration Statement; (ii) the Company's Restated Articles
of Incorporation and Bylaws, as amended to date; (iii) the Plan; (iv) corporate
proceedings relating to the adoption of the Plan and the issuance of the
Shares; and (v) such other documents and records as we have deemed necessary in
order to render this opinion.  In rendering this opinion, we have relied as to
certain factual matters on certificates of officers of the Company and of state
officials.

     Based upon the foregoing, it is our opinion that:

     1. The Company is a corporation validly existing under the laws of the
State of Wisconsin.

     2. The Shares to be sold from time to time pursuant to the Plan which are
original issuance shares will, when issued and paid for as contemplated by the
Registration Statement and the Plan, will be validly issued, fully paid and
non-assessable by the Company, subject to the personal liability which may be
imposed on shareholders by Section 180.0622(2)(b) of the Wisconsin Business
Corporation Law, as judicially interpreted, for debts owing to employees for
services performed, but not exceeding six months service in any one case.
Although Section 180.0622(2)(b) provides that such personal liability of
shareholders shall be "to an amount equal to the par value of shares owned by
them respectively, and to the consideration for which their shares without par
value was issued," the Wisconsin Supreme Court, by a split decision without a
written opinion, has affirmed a judgment holding shareholders of a corporation
liable under the substantially identical predecessor statute in effect prior to
January 1, 1991 (Section 180.40(6)) for unpaid employee wages to an amount
equal to the consideration for which their par value shares were issued rather
than the shares' lower stated par value.  Local 257 of Hotel and Restaurant
Employees and Bartenders International Union v. Wilson Street East Dinner



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Plexus Corp.
June 20, 1996
Page 2


Playhouse, Inc., 126 Wis. 2d 284, 375 N.W.2d 664 (1985) (affirming the 1983
decision of the Circuit Court for Dane County, Wisconsin, in Case No.
82-CV-0023).

     We consent to the filing of this opinion as an Exhibit to the Registration
Statement.  In giving our consent, we do not admit that we are "experts" within
the meaning of Section 11 of the Act, or that we come within the category of
persons whose consent is required by Section 7 of the Act.

                                        Very truly yours,

                                        /s/ Quarles & Brady

                                        QUARLES & BRADY