Hiro Yamamoto (山本 紘, Yamamoto Hiro, born April 13, 1961) is an American bassist who was a founding member of grunge band Soundgarden, along with Kim Thayil and Chris Cornell in 1984. He left the band in 1989, and two years later, he started the independent rock band Truly together with Screaming Trees drummer Mark Pickerel and Robert Roth from The Storybook Krooks. In 2016, Yamamoto co-founded the surf trio Stereo Donkey.