1984 Japan Open Tennis Championships
Date	8–14 October
Edition	11th
Surface	Hard / outdoor
Location	Tokyo, Japan
Champions
Men's singles
David Pate[1]
Women's singles
Lilian Drescher
Men's doubles
David Dowlen / Nduka Odizor[2]
Women's doubles
Betsy Nagelsen / Candy Reynolds
← 1983 · Japan Open · 1985 →

The 1984 Japan Open Tennis Championships was a tennis tournament played on outdoor hard courts in Tokyo, Japan that was part of the 1984 Volvo Grand Prix and the 1984 Virginia Slims World Championship Series. The tournament was held from 8 October through 14 October 1984. David Pate and Lilian Drescher won the singles titles.

Finals

Men's singles

David Pate defeated Terry Moor 6–3, 7–5

• It was Pate's 1st singles title of his career.

Women's singles

Lilian Drescher defeated Shawn Foltz 6–4, 6–2

• It was Drescher' only career title.

Men's doubles

David Dowlen / Nduka Odizor defeated Mark Dickson / Steve Meister 6–7, 6–4, 6–3

• It was Dowlen's 2nd title of the year and the 3rd of his career. It was Odizor's 2nd title of the year and the 5th of her career.

Women's doubles

Betsy Nagelsen / Candy Reynolds defeated Emilse Raponi-Longo / Adriana Villagrán-Reami 6–3, 6–2

• It was Nagelsen's 3rd title of the year and the 14th of her career. It was Reynolds' 3rd title of the year and the 20th of her career.