Seiji Yokoyama (横山 菁児, Yokoyama Seiji) (born March 17, 1935) is a prolific Japanese incidental music composer from Hiroshima who is best known for his work on the Saint Seiya series. He is a graduate student of Kunitachi College of Music. He made his debut as a composer for the ending theme of The Adventures of Hutch the Honeybee in 1974. He is known for his symphonic sound for many television programs.