Powell St. John (born September 18, 1940) is an American singer and songwriter, active on the mid-1960s Austin, Texas campus folk/bohemian music scene. He was an occasional member of various Austin rock groups, including The Conqueroo, and wrote some songs for The 13th Floor Elevators, including "You Don't Know (How Young You Are)", included on the band's 1966 debut, The Psychedelic Sounds of the 13th Floor Elevators.