Ayumi Oka (岡あゆみ, Oka Ayumi, born 13 March 1986) 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.