"A Hard Day's Night" is a song by the English rock band the Beatles. Credited to Lennon–McCartney, it was written by John Lennon, with some collaboration from Paul McCartney.
It was released on the film soundtrack of the same name in 1964. It was also released as a single in the UK (with "Things We Said Today" as its B-side), and in the US (with "I Should Have Known Better" as its B-side.)
The song featured prominently on the soundtrack to the Beatles' first feature film, A Hard Day's Night, and was on their album of the same name. The song topped the charts in both the United Kingdom and United States when it was released as a single.
The American and British singles of "A Hard Day's Night", as well as both the American and British albums of the same title, held the top position in their respective charts simultaneously for a couple of weeks in August 1964, the first time any artist had accomplished this feat.