Isaac Willis (born November 12, 1955) is an singer and guitarist who was a regular sideman for Frank Zappa, first joining Zappa’s band for the 1978 tour. He didn’t tour with Zappa in 1981 and 1982, but returned for Zappa’s final two tours in 1984 and 1988.
Among others, he is featured in Joe’s Garage, Tinsel Town Rebellion, You Are What You Is and is the title character and narrator in Zappa’s off-Broadway-styled conceptual musical Thing-Fish.