"Hey Jude" is a song by the English rock band the Beatles that was released as a non-album single in August 1968. It was written by Paul McCartney and credited to the Lennon–McCartney partnership. The single was the Beatles' first release on their Apple record label and one of the "First Four" singles by Apple's roster of artists, marking the label's public launch. "Hey Jude" was a number-one hit in many countries around the world and became the year's top-selling single in the UK, the US, Australia and Canada. Its nine-week run at number one on the Billboard Hot 100 tied the all-time record in 1968 for the longest run at the top of the US charts. It has sold approximately eight million copies and is frequently included on music critics' lists of the greatest songs of all time.

The writing and recording of "Hey Jude" coincided with a period of upheaval in the Beatles. The ballad evolved from "Hey Jules", a song McCartney wrote to comfort John Lennon's son, Julian, after Lennon had left his wife for the Japanese artist Yoko Ono. The lyrics espouse a positive outlook on a sad situation, while also encouraging "Jude" to pursue his opportunities to find love. After the fourth verse, the song shifts to a coda featuring a "Na-na-na na" refrain that lasts for over four minutes.