Southampton Football Club (/saʊθˈ(h)æmptən/ (listen)) is an English professional football club based in Southampton, Hampshire, which plays in the Premier League, the top tier of English football. One of the founding members of the Premier League, they have spent the majority of their history in the top flight since their first promotion to it in 1966; their longest continuous period was for 27 seasons between 1978 and 2005.

Their home ground since 2001 has been St Mary's Stadium, prior to which they were based at The Dell. The club has been nicknamed "The Saints" since its inception in 1885 due to its history as a church football team, founded as St. Mary's Church of England Young Men's Association, and play in red and white shirts. Southampton have a long-standing rivalry with Portsmouth, due in part to geographic proximity and both cities' respective maritime histories. Matches between the two clubs are known as the South Coast derby.

Southampton were originally founded at St. Mary's Church, on 21 November 1885 by members of the St. Mary's Church of England Young Men's Association.

St. Mary's Y.M.A., as they were usually referred to in the local press, played most of their early games on The Common where games were frequently interrupted by pedestrians insistent on exercising their right to roam. More important matches, such as cup games, were played either at the County Cricket Ground in Northlands Road or the Antelope Cricket Ground in St Mary's Road.