The 1981 Japan Open Tennis Championships was a combined men's and women's tennis tournament played on outdoor hard courts in Tokyo, Japan that was part of the 1981 Avon Championships World Championship Series and the 1981 Volvo Grand Prix.

It was the eighth edition of the tournament and was held from 19 October through 25 October 1981.

Balázs Taróczy and Marie Pinterová won the singles titles.

Balázs Taróczy defeated Eliot Teltscher 6–3, 1–6, 7–6 Marie Pinterová defeated Pam Casale 2–6, 6–4, 6–1 Balázs Taróczy / Heinz Günthardt defeated Larry Stefanki / Robert Van't Hof 3–6, 6–2, 6–1 Patricia Medrado / Cláudia Monteiro defeated Barbara Jordan / Roberta McCallum 6–3, 3–6, 6–2