Barbara "Sandi" Robison (born Barbara Jeane Moyer, October 14, 1945 – April 22, 1988), also known as Sandi Peanut Butter, was an American singer who achieved the most success as the lead vocalist for the psychedelic rock band, The Peanut Butter Conspiracy. Robison was one of the earliest female vocalists of a rock band, and was involved in other acts after the group's disbandment, including the musical, Hair.