2005 AIG Japan Open Tennis Championships
Date	3–9 October
Edition	32nd
Surface	Hard / outdoor
Location	Tokyo, Japan
Venue	Ariake Coliseum
Champions
Men's singles
Wesley Moodie[1]
Women's singles
Nicole Vaidišová
Men's doubles
Satoshi Iwabuchi / Takao Suzuki[2]
Women's doubles
Gisela Dulko / Maria Kirilenko
← 2004 · Japan Open · 2006 →

The 2005 AIG Japan Open Tennis Championships was a tennis tournament played on outdoor hard courts. It was the 32nd edition of the event known that year as the AIG Japan Open Tennis Championships, and was part of the International Series Gold of the 2005 ATP Tour, and of the Tier III Series of the 2005 WTA Tour. Both the men's and the women's events took place at the Ariake Coliseum in Tokyo, Japan, from 3 October through 9 October 2005. Wesley Moodie and Nicole Vaidišová won the singles titles.

Finals

Men's singles

Wesley Moodie defeated Mario Ančić, 1–6, 7–6^(9–7), 6–4 ^[3]

• It was Moodie's 1st title of the year and the 1st of his career.

Women's singles

Nicole Vaidišová defeated Tatiana Golovin, 7–6^(7–4), 3–2, retired^[4]

• It was Vaidišová's 2nd title of the year and the 4th of her career.

Men's doubles

Satoshi Iwabuchi / Takao Suzuki defeated Simon Aspelin / Todd Perry, 5–4^(7–3), 5–4^(15–13)

• It was the first and only title for both Iwabuchi and Suzuki.

Women's doubles

Gisela Dulko / Maria Kirilenko defeated Shinobu Asagoe / María Vento-Kabchi, 7–5, 4–6, 6–3