Chelsea Football Club is a professional football club based in Fulham, West London, England. The club was founded in 1905 and named after neighbouring area Chelsea. They compete in the Premier League, the top tier of English football, playing their home games at Stamford Bridge. Since 2022, the club has been owned by BlueCo.

Chelsea won their first major domestic honour, the First Division championship, in 1955. Domestically, Chelsea have won six top-flight league titles, eight FA Cups, five League Cups, and four FA Community Shields, making them the fifth-most successful club in English football.

At international level, Chelsea won their first trophy in 1971, when they won the European Cup Winners' Cup. After winning another Cup Winners' Cup in 1998, they went on to win their first UEFA Champions League in 2012, a feat they repeated in 2021. Chelsea have also won the UEFA Europa League twice, in 2013 and 2019. After winning the UEFA Conference League in 2025, Chelsea became the first club to win all four main UEFA competitions. Additionally, they won the FIFA Club World Cup in 2022, becoming the third English club to do so.

Chelsea have rivalries with fellow London teams Arsenal and Tottenham Hotspur, and also with Leeds United.