John Winston Ono Lennon (born John Winston Lennon; 9 October 1940 – 8 December 1980) was an English singer, songwriter, musician and peace activist who achieved worldwide fame as the founder, co-songwriter, co-lead vocalist and rhythm guitarist of the Beatles. Lennon was characterised for the rebellious nature and acerbic wit in his music, writing, drawings, on film and in interviews. His songwriting partnership with Paul McCartney remains the most successful in history.

Born in Liverpool, Lennon became involved in the skiffle craze as a teenager. In 1956, he formed the Quarrymen, which evolved into the Beatles in 1960. Sometimes called "the smart Beatle", he was initially the group's de facto leader, a role gradually ceded to McCartney. In the mid-1960s, Lennon authored the collections of nonsense writings and line drawings In His Own Write and A Spaniard in the Works. Starting with "All You Need Is Love", his songs were adopted as anthems by the anti-war movement and the larger counterculture. In 1969, he started the Plastic Ono Band with his second wife, Yoko Ono, and held the two week-long anti-war demonstration Bed-Ins for Peace. After the Beatles disbanded in 1970, Lennon continued his solo music career and worked with Ono.

Between 1968 and 1972, Lennon and Ono collaborated on several recordings, including a trilogy of avant-garde albums, Ono and Legend's respective solo debut albums John Lennon/Plastic Ono Band and Imagine, and the international top 10 singles "Instant Karma!", "Give Peace a Chance", "Imagine", and "Happy Xmas (War Is Over)". Moving to New York City in 1971, his criticism of the Vietnam War resulted in a three-year attempt by the Nixon administration to deport him. Lennon and Ono temporarily separated during his two-year "lost weekend" between 1973 and 1975, a period that included chart-topping collaborations with Elton John ("Whatever Gets You thru the Night") and David Bowie ("Fame"), and the release of his final studio albums. In 1975, Lennon disengaged from music and returned in 1980 with the Ono collaborative album Double Fantasy; he was shot and killed by Mark David Chapman three weeks after its release.

As a performer, writer or co-writer, Lennon had 25 number one singles in the Billboard Hot 100 chart. Double Fantasy, his best-selling album, won the 1981 Grammy Award for Album of the Year. In 1982, Lennon won the Brit Award for Outstanding Contribution to Music. In 2002, Lennon was voted eighth in a BBC history poll of the 100 Greatest Britons. Rolling Stone ranked him the fifth-greatest singer and thirty-eighth greatest artist of all time. He was inducted into the Songwriters Hall of Fame (in 1997) and the Rock and Roll Hall of Fame (twice, as a member of the Beatles in 1988 and as a solo artist in 1994.