Oka is a surname. Notable people with the surname include:
Arsene Oka (born 1983), Côte d'Ivoire football (soccer) player
Asajiro Oka (丘浅次郎 Oka Asajirō, 1866–1944), Japanese zoologist, anatomist and evolutionist
Ayumi Oka (born 1983), Japanese actress
Ayumi Oka (born 1986), Japanese female tennis player
Gedong Bagus Oka (1921–2002), Hindu reformer and philosopher in Indonesia
Kazuo Oka (born 1948), Japanese voice actor
Kiyoshi Oka (1901–1978), Japanese mathematician
Masi Oka (born 1974), Japanese American actor and digital effects artist
Takeshi Oka (born 1932), Japanese-American chemist and astronomer
