`` Lucy in the Sky with Diamonds '' is a song written by John Lennon and Paul McCartney for the Beatles ' 1967 album Sgt. Pepper 's Lonely Hearts Club Band . `` Lucy in the Sky with Diamonds '' is a song written primarily by John Lennon and credited to Lennon\/McCartney , for The Beatles ' 1967 album Sgt. Pepper 's Lonely Hearts Club Band .