Nicholas Berkeley Mason (born 27 January 1944) is an English drummer and a founder member of the rock band Pink Floyd. He has been the only constant member since the band's formation in 1965, and the only member to appear on every Pink Floyd album. He co-wrote Pink Floyd compositions including "Echoes", "Time", "Careful with That Axe, Eugene" and "One of These Days".

In 1996, Mason was inducted into the Rock and Roll Hall of Fame as a member of Pink Floyd. In 2018, he formed a new band, Nick Mason's Saucerful of Secrets, to perform music from Pink Floyd's early years. Mason collects classic cars and competes in motorsport races, and has produced books and documentaries on the subject.

Mason was born on 27 January 1944 in Birmingham to Ailsa Sarah (née Kershaw) and Bill Mason, a documentary filmmaker; one of his paternal great-grandfathers was Rowland Hill Berkeley, who was Lord Mayor of Birmingham in 1904–1905.

Mason was brought up in Hampstead, London, and attended the Hall School, Hampstead, and Frensham Heights School, near Farnham, Surrey. While studying architecture at the Regent Street Polytechnic (now the University of Westminster), he formed a band, Sigma 6, an early incarnation of Pink Floyd, with Roger Waters, Bob Klose and Richard Wright in 1964. In September 1963, Waters and Mason moved into a flat near Crouch End in London, owned by Mike Leonard, a part-time tutor at the nearby Hornsey College of Art and the Regent Street Polytechnic. Mason moved out after the 1964 academic year.

Pink Floyd released their debut album, The Piper at the Gates of Dawn, in 1967. Mason has played on every Pink Floyd album since. The only Pink Floyd compositions credited solely to Mason are "The Grand Vizier's Garden Party" (from Ummagumma) and "Speak to Me" (from The Dark Side of the Moon). The track "Nick's Boogie" was named after him.

The only occasions on which Mason's voice has been included on Pink Floyd's albums are "Corporal Clegg"; the single spoken line in "One of These Days"; and spoken parts of "Signs of Life" and "Learning to Fly" (the latter taken from an actual recording of Mason's first solo flight) from A Momentary Lapse of Reason. He sang lead vocals on two unreleased but heavily bootlegged tracks, "Scream Thy Last Scream" (1967), penned by original group leader Syd Barrett, and "The Merry Xmas Song" (1975–76). In live performances of the song "Sheep", Mason delivered the spoken section.

Despite legal conflicts over ownership of the name "Pink Floyd", which began when Waters left the group in 1985 and lasted roughly seven years, Waters and Mason are reportedly on good terms. Mason joined Waters on the last two nights of his 2002 world tour to play drums on the Pink Floyd song "Set the Controls for the Heart of the Sun", and he also played drums on some concerts of Waters' European tour in 2006, and during performances in Los Angeles and New York City in the United States.

In July 2005, Mason, Gilmour, Wright, and Waters played together on stage for the first time in 24 years at the Live 8 concert in London. Mason joined Gilmour and Wright again for the encore during Gilmour's show at the Royal Albert Hall, London, on 31 May 2006. He also stated in 2006 that Pink Floyd had not officially disbanded, but with the death of Wright in 2008, the band effectively came to an end, as confirmed by Gilmour. While Gilmour and Waters continued to quarrel, Mason remained close to both.