Adelaide United Football Club (known as "Adelaide United", English name: Adelaide United FC) was founded on September 12, 2003, and is a professional men's football club located in Adelaide, South Australia, Australia. As one of the eight founding teams of the A-League Men, it has participated in the league since its inception and is the only professional football club in South Australia.
In October 2003, the team achieved its first victory in the National Soccer League. After joining the A-League, the team won the regular season championship in 2006. In 2008, it became the first Australian team to reach the AFC Champions League final. In January 2011, the team achieved a record-breaking 8-1 victory over North Queensland Fury at home. In 2014, the team won the first Australia Cup final. Two years later, the team won the A-League Grand Final against Western Sydney Wanderers, claiming the club's first A-League title. From 2018 to 2019, the team won the Australia Cup for two consecutive years, becoming the most successful club in the competition.
Before the 2009-10 season, the club faced a financial crisis when the original owner returned the operating license. The Australian Football Federation took over the financial management and ensured operations, but the team also suffered its worst-ever performance, finishing last. In November 2010, a South Australian consortium took over the club, acquiring a ten-year operating license and completing a change of ownership.