Seiji Yokoyama (横山菁児, Yokoyama Seiji, March 17, 1935 - July 8, 2017) was a prolific Japanese incidental music composer best known for his work on the Space Pirate Captain Harlock and Saint Seiya series. Yokoyama was born in Hiroshima. He was 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 1971. He was known for his symphonic sound for many television programs.