Koichi Yamadera (born June 17, 1961) is a Japanese voice actor and radio host best known as the voice of Spike Spiegel in the anime Cowboy Bebop, as well as commonly dubbing actors such as Robin Williams, Eddie Murphy and Jim Carrey, and providing the Japanese voice for Disney characters such as Donald Duck and Stitch.

He provided the Japanese language voice for Kermit the Frog, Sam the Eagle, Animal in The Muppet Christmas Carol.