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.
David Pate defeated Terry Moor 6–3, 7–5
Lilian Drescher defeated Shawn Foltz 6–4, 6–2
David Dowlen / Nduka Odizor defeated Mark Dickson / Steve Meister 6–7, 6–4, 6–3
Betsy Nagelsen / Candy Reynolds defeated Emilse Raponi-Longo / Adriana Villagrán-Reami 6–3, 6–2