<PAGE>
EXHIBIT 5.3
August 3, 2000
Tyco International Ltd.
The Zurich Centre, Second Floor
90 Pitts Bay Road
Pembroke HM 08, Bermuda
Tyco International Group S.A.
6, avenue Emile Reuter
Second Floor
L-2420 Luxembourg
Ladies and Gentlemen:
We have acted as special counsel to Tyco International Ltd., a Bermuda
company ("Tyco"), and Tyco International Group S.A., a Luxembourg company (the
"Issuer"), in connection with Amendment No. 1 to the Registration Statement on
Form S-4 (File Nos. 333-42128 and 333-42128-01) (the "Registration Statement")
filed by Tyco and the Issuer with the United States Securities and Exchange
Commission (the "Commission") under the Securities Act of 1933, as amended, for
the registration of (Euro)600,000,000 aggregate principal amount of the
Issuer's 6 1/8% Notes due 2007 (the "Debt Securities") and the guarantee (the
"Guarantee") of the Debt Securities by Tyco, to be issued upon consummation of
the exchange offer referred to in the Registration Statement (the "Exchange
Offer"). The Debt Securities will be issued as a single series pursuant to an
Indenture filed as Exhibit 4.1 to the Registration Statement (the "Indenture"),
and as supplemented by Supplemental Indenture No. 13 filed as Exhibit 4.2 to
the Registration Statement (the "Supplemental Indenture") among the Issuer,
Tyco (as Guarantor) and the trustee thereunder.
We have examined originals or copies, certified or otherwise identified to
our satisfaction, of such documents, corporate records, certificates of public
officials and other instruments as we have deemed necessary or advisable for
the purposes of rendering this opinion. In addition, we have examined and
relied upon the opinions of Appleby, Spurling & Kempe, Bermuda counsel to Tyco,
and Beghin & Feider in association with Allen & Overy, Luxembourg counsel to
the Issuer, of even date.
With respect to the Debt Securities, when such Debt Securities have been
duly executed, authenticated, issued and delivered in accordance with the
provisions of the Indenture, and the applicable supplemental indentures, and
upon the terms of the Exchange Offer set forth in the Registration Statement,
the Debt Securities will be legally issued and will constitute valid and
binding obligations of the Issuer, enforceable against the Issuer in accordance
with their terms, except as such enforcement is subject to any applicable
bankruptcy, insolvency, reorganization, moratorium, fraudulent conveyance or
other law relating to or affecting creditors' rights and remedies generally and
general principles of equity.
With respect to the Guarantee, when the Guarantee has been duly executed,
authenticated, issued and delivered in accordance with the provisions of the
Indenture and the applicable supplemental indentures, and upon the terms of the
Exchange Offer set forth in the Registration Statement, the Guarantee will be
legally issued and will constitute the valid and binding obligation of Tyco,
enforceable against Tyco in accordance with its terms, except as such
enforcement is subject to any applicable bankruptcy, insolvency,
reorganization, moratorium, fraudulent conveyance or other law relating to or
affecting creditors' rights and remedies generally and general principles of
equity.
We are members of the Bar of the State of New York and the foregoing opinion
is limited to the laws of the State of New York and the federal laws of the
United States.
<PAGE>
In connection with the foregoing, we have assumed that at the time of the
issuance and delivery of the Exchange Notes and the Guarantee there will not
have occurred any change in law affecting the validity, legally binding
character or enforceability of the Exchange Notes and the Guarantee and that
the issuance and delivery of the Exchange Notes and Guarantee, all of the terms
of the Exchange Notes and the Guarantee and the performance by the Issuer and
Tyco of their respective obligations under the Exchange Notes and Guarantee
will comply with all applicable law and with each requirement or restriction
imposed by any court or governmental body having jurisdiction over the Issuer
or Tyco and will not result in a default under or a breach of any agreement or
instrument then binding upon the Issuer or Tyco.
In rendering the foregoing opinion, we have relied as to certain matters on
information obtained from public officials, officers of the Issuer and Tyco and
other sources believed by us to be responsible, and we have assumed (i) that
the Indenture as supplemented by Supplemental Indenture No. 13, has been duly
authorized, executed and delivered by the Trustee, (ii) that the Exchange Notes
will conform to the specimens thereof examined by us, (iii) that the Trustee's
certificate of authentication of the Exchange Notes will be manually signed by
one of the Trustee's authorized officers and (iv) that the signatures on all
documents examined by us are genuine, assumptions which we have not
independently verified.
We hereby consent to the filing of this opinion as an exhibit to the
Registration Statement and to the statements made with respect to us under the
caption "Legal Matters" in the prospectus included as part of the Registration
Statement.
Very truly yours,
/s/ Davis Polk & Wardwell
2
