Osamu Ota (太田 治, Ota Osamu) (born 23 March 1965, in Akita) is a former Japanese rugby union player and a coach.
Ota had 27 caps for Japan, from 1986 to 1995, scoring a try, 5 points in aggregate.
Ota, after finishing his player career, become a coach.
He was general manager of Japan Rugby Football Union when he took charge as caretaker head coach of the "Brave Blossoms", in September 2006, after the sacking of Jean-Pierre Élissalde.
He announced that the new head coach of Japan would be John Kirwan, in October, remaining in office until 1 January 2007.