"I Want You (She's So Heavy)" is a song by the English rock band the Beatles, written by John Lennon and credited to Lennon–McCartney. The song closes side one of their 1969 album Abbey Road and features Billy Preston playing the organ. It was the first song recorded for the Abbey Road album but one of the last songs to be finished; the band gathered in the studio to mix the song on 20 August 1969, marking the final time that all four Beatles were together in the studio.

The song, initially titled "I Want You", was rehearsed several times during the Get Back/Let It Be sessions, with the first one being on 29 January 1969 at Apple Records. The basic track, and Lennon's guide vocal (which is used in the master), were recorded at Trident Studios on 22 February, shortly after shooting for the Let It Be film ended. Lennon played the lead guitar, as Harrison stated:

It's very heavy. John plays lead guitar and sings the same as he plays. It's really basically a bit like a blues. The riff that he sings and plays is really a very basic blues-type thing. But again, it's very original sort of John-type song.

Lennon and Harrison overdubbed multi-tracked heavy guitars on 18 April 1969. Billy Preston's Hammond organ and Ringo Starr's congas were added on 20 April 1969. "I Want You" received the "She's So Heavy" vocals on 11 August, and thus the title became "I Want You (She's So Heavy)". "'She's So Heavy' was about Yoko," Lennon told Rolling Stone. "When you're drowning, you don't say, 'I would be incredibly pleased if someone would have the foresight to notice me drowning and come and help me.' You just scream."