Exhibit 21

PREFORMED LINE PRODUCTS COMPANY

SUBSIDIARIES

Domestic Subsidiaries:

Superior Modular Products Incorporated

Asheville, North Carolina

Foreign Subsidiaries:

Australia

Preformed Line Products (Australia) Ltd.

Sydney, Australia

Rack Technologies Pty. Ltd.

Sydney, Australia

Brazil

PLP-Produtos Para Linhas Preformados Ltd.

Sao Paulo, Brazil

Canada

Preformed Line Products (Canada) Ltd.

Cambridge, Ontario, Canada

China

Beijing PLP Conductor Line Products Co., Ltd.

Beijing, China

Mexico

Preformados de Mexico S.A. de C.V.

Queretaro, Mexico

South Africa

Preformed Line Products (South Africa) Pty. Ltd.

Pietermaritzburg, Natal

Republic of South Africa

Spain

APRESA – PLP Spain, S. A.

Sevilla, Spain

Thailand

Preformed Line Products (Asia) Ltd.

Bangkok, Thailand

United Kingdom

Preformed Line Products (Great Britain) Ltd.

Andover, Hampshire, England