| Ayumi Oka | |
| Birth Date: | 1986 3, df=y |
| Birth Place: | Hyogo, Japan[1] |
| Plays: | Right (two-handed backhand) |
| Careerprizemoney: | $89,103 |
| Singlestitles: | 2 ITF |
| Highestsinglesranking: | No. 297 (15 June 2009) |
| Doublestitles: | 13 ITF |
| Highestdoublesranking: | No. 219 (7 July 2010) |
is a Japanese former professional tennis player. Most time of her career, she played on the ITF Women's Circuit.
In June 2009, she reached her highest singles ranking of 297 by the Women's Tennis Association (WTA). In July 2010, she reached her best WTA doubles ranking of 219.
| $100,000 tournaments | |
| $75,000 tournaments | |
| $50,000 tournaments | |
| $25,000 tournaments | |
| $10,000 tournaments |
| Outcome | No. | Date | Tournament | Surface | Opponent | Score | |
|---|---|---|---|---|---|---|---|
| Winner | 1. | 9 September 2007 | ITF Kyoto, Japan | Carpet (i) |  Haruka Fujishiro | 6–1, 4–6, 6–3 | |
| Winner | 2. | 22 August 2011 | ITF Saitama, Japan | Hard |  Duan Yingying | 6–3, 6–4 |
| Outcome | No. | Date | Tournament | Surface | Partner | Opponents | Score | |
|---|---|---|---|---|---|---|---|---|
| Winner | 1. | 12 June 2005 | ITF Tokyo, Japan | Hard | Natsuko Kurita | Nozomi Aiba Kana Okawa | 6–3, 6–4 | |
| Winner | 2. | 4 June 2007 | ITF Tokyo, Japan | Hard | Mari Tanaka | Tomoko Taira Etsuko Kitazaki | 3–6, 6–1, 6–4 | |
| Winner | 3. | 22 July 2007 | Kurume Cup, Japan | Grass | Tomoko Sugano | Liu Wanting Song Shanshan | 6–4, 6–1 | |
| Winner | 4. | 22 September 2007 | Tsukuba, Japan | Hard | Tomoko Sugano | Natsumi Hamamura Ayaka Maekawa | 6–2, 6–3 | |
| Runner-up | 5. | 19 November 2007 | Manila, Philippines | Hard | Kei Sekine | Chen Yi Kao Shao-yuan | 6–7(5–7), 1–6 | |
| Runner-up | 6. | 3 May 2008 | Balikpapan, Indonesia | Hard | Tomoko Sugano | Sandy Gumulya Lavinia Tananta | 3–6, 6–4, [7–10] | |
| Winner | 7. | 22 June 2008 | Sutama, Japan | Clay | Ayaka Maekawa | Kazusa Ito Tomoko Taira | 6–3, 6–4 | |
| Runner-up | 8. | 13 July 2008 | Tokyo, Japan | Carpet |  Varatchaya Wongteanchai |  Chang Kyung-mi Chae Kyung-yee | 6–3, 2–6, [7–10] | |
| Winner | 9. | 20 September 2008 | Kyoto, Japan | Carpet (i) | Varatchaya Wongteanchai | Maki Arai Yurina Koshino | 5–7, 6–2, [10–2] | |
| Runner-up | 10. | 1 June 2009 | Komoro, Japan | Clay | Varatchaya Wongteanchai | Zhang Shuai Xu Yifan | 2–6, 1–6 | |
| Winner | 11. | 8 June 2009 | Tokyo, Japan | Hard | Mari Tanaka | Maki Arai Yurina Koshino | 7–6, 6–0 | |
| Winner | 12. | 2 August 2009 | Obihiro, Japan | Carpet | Natsumi Hamamura | Rika Fujiwara Kurumi Nara | 3–6, 6–1, [10–5] | |
| Winner | 13. | 23 May 2010 | Karuizawa, Japan | Carpet | Akiko Yonemura | Sun Shengnan Xu Yifan | 7–6 (7–1), 6–3 | |
| Runner-up | 14. | 2 August 2010 | Niigata, Japan | Carpet | Miki Miyamura | Akari Inoue Kotomi Takahata | 1–6, 4–6 | |
| Runner-up | 15. | 19 September 2010 | Kyoto, Japan | Carpet (i) | Kaori Onishi | Kazusa Ito Tomoko Taira | 3–6, 6–7(5–7) | |
| Winner | 16. | 20 March 2011 | Miyazaki, Japan | Carpet | Mari Inoue | Chinami Ogi Yuuki Tanaka | 5–7, 6–2, [10–8] | |
| Winner | 17. | 15 May 2011 | Kurume Cup, Japan | Grass | Akiko Yonemura | Rika Fujiwara Tamarine Tanasugarn | 6–3, 5–7, [10–8] | |
| Runner-up | 18. | 22 May 2011 | Karuizawa, Japan | Carpet (i) | Natsumi Hamamura | Rika Fujiwara Shuko Aoyama | 4–6, 4–6 | |
| Runner-up | 19. | 14 May 2011 | Niigata, Japan | Hard | Akari Inoue | Natsumi Hamamura Erika Sema | 1–6, 2–6 | |
| Runner-up | 20. | 22 August 2011 | Saitama, Japan | Hard | Akari Inoue | Liu Wanting Liang Chen | 3–6, 7–5, [9–11] | |
| Runner-up | 21. | 11 September 2011 | Nato, Japan | Carpet | Natsumi Hamamura | Kanae Hisami Varatchaya Wongteanchai | 6–1, 6–7(4–7), [12–14] | |
| Winner | 22. | 30 October 2011 | Hamanako, Japan | Carpet | Natsumi Hamamura | Huỳnh Phương Đài Trang Varatchaya Wongteanchai | 6–3, 6–3 | |
| Winner | 23. | 23 March 2012 | ITF Kofu, Japan | Hard | Kotomi Takahata | Eri Hozumi Remi Tezuka | 6–4, 5–7, [10–3] |