"There's a Rainbow 'Round My Shoulder" is a 1928 song sung by Al Jolson in the early Warner Bros. talking picture The Singing Fool the same year. The song, along with "Sonny Boy" and "I'm Sitting on Top of the World", which were also in The Singing Fool, were big hits for Jolson. The song was written by Al Jolson, Billy Rose and Dave Dreyer.
According to John A. Lomax in his "American Ballads and Folk Songs" published in 1934, from the song "Goin' Home". The line "Got a rainbow tied all 'round my shoulder" refers to the "Rainbow" as "the arc of a swinging pick, probably going so fast it becomes red hot." This song is in the section entitled "Songs from Southern Chain Gangs".