Isaac Willis is an American vocalist and guitarist who was a regular member of Frank Zappa's studio and touring bands from 1978 until the last tour in 1988. He did not tour with Zappa in 1981 and 1982 because he wanted to be at home for the birth of his two children, and returned to touring with Zappa for his final two tours in 1984 and 1988. He currently tours with the Frank Zappa tribute bands Bogus Pomp, Ossi Duri, Project/Object, Pojama People, Ugly Radio Rebellion and ZAPPATiKA. He also performed several times with the Brazilian Zappa cover band, The Central Scrutinizer Band, The Muffin Men, and with the Italian bands Ossi Duri and Elio e le Storie Tese. Additionally, he has appeared multiple times at the annual Zappanale Festival in Bad Doberan, Germany. He is most recognized for his involvement in Zappa records such as playing Joe in Joe's Garage, providing vocals on Tinsel Town Rebellion, You Are What You Is, and The Man from Utopia, and as the title character and narrator in Zappa's off-Broadway-styled conceptual musical Thing-Fish.
Willis also regularly does studio voice work and writes compositions for films. He also creates solo music and leads The Ike Willis Band.