From 18 August 1962 to 20 September 1969, the Beatles consisted of John Lennon, Paul McCartney, George Harrison and Ringo Starr. Their break-up is attributed to numerous factors, including: the strain of the Beatlemania phenomenon, the 1967 death of manager Brian Epstein, bandmates' resentment of McCartney's perceived domineering, Lennon's heroin use and his relationship with Yoko Ono, Harrison's increasingly prolific songwriting, the floundering of Apple Corps, the Get Back project (renamed Let It Be in 1970), and managerial disputes.

During the latter half of the 1960s, the members began to assert individual artistic agendas. Their disunity became most evident on 1968's The Beatles (also known as "the White Album"), and quarrels and disharmony over musical matters soon permeated their business discussions. Starr left the group for two weeks during the White Album sessions, and Harrison quit for five days during the Get Back rehearsals. Starting in 1969, the group split into two camps regarding who should handle their business affairs. McCartney lobbied for entertainment lawyers Lee and John Eastman, but was outvoted by his bandmates in favour of businessman Allen Klein.

The final time that the four members recorded together was the session for Abbey Road's "The End" on 20 August 1969, a date which also saw further mixing and editing for "I Want You (She's So Heavy)"; their final meeting with all four present was two days later at a photo session held at Lennon's Tittenhurst estate. On 20 September, Lennon privately informed his bandmates at a meeting at Apple, without Harrison present, that he was leaving the Beatles, although it was unclear to the other members whether his departure was permanent. On 10 April 1970, McCartney said in a press release that he was no longer working with the group, which sparked a widespread media reaction and worsened the tensions between him and his bandmates. Legal disputes continued long after his announcement, and the dissolution was not formalised until 29 December 1974.

Rumours of a full-fledged reunion persisted throughout the 1970s, as the members occasionally reunited for collaboration, but never with all four simultaneously. Starr's "I'm the Greatest" (1973) and Harrison's "All Those Years Ago" (1981) are the only tracks that feature three ex-Beatles. After Lennon's murder in 1980, the surviving members reunited for the Anthology project in 1994, using the unfinished Lennon demos "Free as a Bird" and "Real Love" as the basis for new songs recorded and released as the Beatles.