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                                                                     EXHIBIT 5.1


                     [On the letterhead of Allen & Gledhill]



Flextronics International Ltd.
11 Ubi Road 1,
#07-01/02 Meiban Industrial Building,
Singapore 408723                                            27th September, 2000

Dear Sirs,

                      REGISTRATION STATEMENT ON FORM S-3 OF
                 FLEXTRONICS INTERNATIONAL LTD. (THE "COMPANY")

     We refer to the Registration Statement on Form S-3 (the "REGISTRATION
STATEMENT") filed or to be filed by the Company with the Securities Exchange
Commission on or about 27th September, 2000 in connection with the Company's
proposed issuance and sale, from time to time, of up to 30,000,000 ordinary
shares of $0.01 each in the capital of the Company ("ORDINARY SHARES") to which
the Registration Statement relates (the "COMPANY SHARES"). You have advised us
that the Company Shares may be sold from time to time on a delayed or continuous
basis as set forth in the Registration Statement, the Prospectus contained
therein and the supplements to the Prospectus.

     In this connection, we are familiar with the corporate proceedings taken by
the Company in connection with the issuance and sale of its Ordinary Shares. We
have also reviewed the Registration Statement, and we have made such other
examinations of law and fact as we considered necessary in order to form a basis
for the opinion hereafter expressed.

     Based on the foregoing and assuming that:

     (i)  the total issued and paid-up share capital of the Company consequent
          upon the issue of the Company Shares from time to time will not exceed
          the authorised share capital of the Company at any time; and

     (ii) there shall be subsisting a valid authority given pursuant to Section
          161 of the Singapore Companies Act, Chapter 50 in respect of the issue
          of the Company Shares from time to time,

     we are of the opinion that, the Company Shares have been duly authorised,
and that upon the passing of the requisite resolutions to allot the Company
Shares and the issue of the certificates representing the Company Shares in
accordance with the Articles of Association of the Company against fully payment
therefor, the Company Shares will be legally issued and fully-paid.

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ALLEN & GLEDHILL                                                      PAGE NO. 2



     This opinion only relates to the laws of general application of Singapore
as at the date hereof and as currently applied by the Singapore courts, and is
given on the basis that it will be governed by and construed in accordance with
the laws of Singapore. We have made no investigation of, and do not express or
imply any views on, the laws, rules or regulations of any country other than
Singapore. In respect of the issuance of the Company Shares from time to time,
we have in particular assumed that the Company has complied or will comply with
all matters of United States Federal and California laws, rules and regulations
prevailing from time to time.

     We consent to the filing of this opinion as exhibit 5.1 to the Registration
Statement and to the reference to this firm under the caption "Legal Matters" in
the Prospectus which forms part of the Registration Statement.

                                       Yours faithfully,

                                       /s/ Allen & Gledhill