Sutton United Football Club is a professional football club from Sutton, South London, England, who play in League Two, the fourth tier of the English football league system. They play home games at Gander Green Lane in Sutton about 11 miles south-southwest of central London.

Sutton started out playing in junior, local leagues, but progressed into the Athenian League in 1921; the Isthmian League in 1964; and the Conference in 1986. The team fell back into the Isthmian League in 1991. Sutton won the Athenian League three times (1927–28, 1945–46 and 1957–58) and the Isthmian League five times (1966–67, 1984–85, 1985–86, 1998–99 and 2010–11). They appeared in the Conference for one more season in 1999–2000, and were founding members of the Conference South (now known as National League South) in 2004. Sutton won the National League South in 2015–16 and achieved their very first promotion to the Football League after winning the National League title in the 2020–21 season.

The team has played at Wembley Stadium on four occasions. Firstly, in the FA Amateur Cup final twice, the FA Trophy final in 1980–81 and the EFL Trophy final in 2021–22. Sutton won the Anglo-Italian Cup in 1978–79, but the club is most famous for its FA Cup "giant killing" exploits, most notably in the 1988–89 season, when they defeated Coventry City 2–1 in the third round. The Coventry City team was composed mostly of star international players and had won the competition in 1986–87. In the 2016–17 season, Sutton reached the fifth round of the FA Cup for the first time in their history, beating three Football League teams (including Leeds United) before losing to Arsenal.