The 1999 Japan Open Tennis Championships was a tennis tournament played on outdoor hard courts at the Ariake Coliseum in Tokyo, Japan that was part of the International Series Gold of the 1999 ATP Tour and of Tier III of the 1999 WTA Tour.

Nicolas Kiefer and Amy Frazier won the singles titles.

The following players received wildcards into the singles main draw: The following players received wildcards into the doubles main draw: The following players received entry from the singles qualifying draw: The following players received entry as lucky losers: Nicolas Kiefer defeated Wayne Ferreira, 7–6(7–5), 7–5.

[3] Jeff Tarango / Daniel Vacek defeated Wayne Black / Brian MacPhie, 4–3, retired.

[1] Corina Morariu / Kimberly Po defeated Catherine Barclay / Kerry-Anne Guse, 6–3, 6–2.