Kōji Seto (瀬戸 康史, Seto Kōji; born May 18, 1988) is a Japanese actor and singer associated with D-Boys, an acting troupe produced by Watanabe Entertainment. His major works include lead roles as Wataru Kurenai in Kamen Rider Kiva; and supporting roles as Satoru Okura in Atashinchi no Danshi, Ariake Yamato in Otomen, and Eiji Kikumaru in Musical: The Prince of Tennis. He starred as Mori Ranmaru in the drama, Gō: Hime-tachi no Sengoku.
In 2010, he was named one of the most promising actors and actresses, placing 7th in a poll conducted by Oricon. Through his role with Kamen Rider Kiva, he was also the lead vocalist of their promotional rock band Tetra-Fang.
