Harry "Doc" Bagby (né Harry Camilus Bagby; 1 August 1917 Philadelphia – 3 September 1970 Manhattan) was an American studio musician who played piano and organ, and backed many artists in pop and jazz. He played a major part in the music scene from the late 1940s to the late 1960s. He was also a bandleader and solo artist in his own right. He released many singles throughout his career. He is also the co-composer of the hit song "Rock the Joint" which has been recorded by Jimmy Preston and Bill Haley.