"When I'm Sixty-Four" is a song by the English rock band The Beatles, written by Paul McCartney and released on their 1967 album Sgt. Pepper's Lonely Hearts Club Band. It was one of the first songs McCartney wrote; he was about 14, probably in April or May 1956. The song was recorded in a key different from the final recording; it was sped up at the request of McCartney to make his voice sound younger. It prominently features a trio of clarinets throughout.

Sir James Paul McCartney is an English singer, songwriter and musician who gained worldwide fame with the Beatles, for whom he played bass guitar and shared primary songwriting and lead vocal duties with John Lennon. One of the most successful composers and performers of all time, McCartney is known for his melodic approach to bass-playing, versatile and wide tenor vocal range, and musical eclecticism, exploring genres ranging from pre–rock and roll pop to classical, ballads, and electronica. His songwriting partnership with Lennon is the most successful in modern music history.