Seiji Oko (大古 誠司 Ōko Seiji , born 15 February 1948) is a former volleyball player from Japan, who was a member of the Japan Men's National Team that won the gold medal at the 1972 Summer Olympics and the silver medal at the 1968 Summer Olympics.[1]
In 2004, he became an inductee of the Volleyball Hall of Fame in Holyoke, Massachusetts.