"When I'm Sixty-Four" is a song by the Beatles, written by Paul McCartney (credited to Lennon–McCartney) and released in 1967 on their album Sgt. Pepper's Lonely Hearts Club Band.
The song is sung by a young man to his lover, and is about his plans of growing old together with her. Although the theme is ageing, it was one of the first songs McCartney wrote, when he was 16. It was on the Beatles playlist in their early days as a song to perform when their amplifiers broke down or the electricity went off. Both George Martin and Mark Lewisohn speculated that McCartney may have thought of the song when recording began for Sgt. Pepper in December 1966 because his father turned 64 earlier that year.
Lennon said of the song, "Paul wrote it in the Cavern days. We just stuck a few more words on it like 'grandchildren on your knee' and 'Vera, Chuck and Dave' ... this was just one that was quite a hit with us." In his 1980 interview for Playboy he said, "I would never even dream of writing a song like that."