A German professional football club based in the St. Pauli district of Hamburg, that competes in the 2. Bundesliga. The football department is part of a larger sports club that also has departments in rugby (FC St. Pauli Rugby), baseball, bowling, boxing (FC St. Pauli Boxen), chess, cycling, handball, roller derby (Harbor Girls Hamburg), skittles, softball, and table tennis and since 2011 Marathon. Until the end of 2013, the club also had a department in American football, but it was dissolved because it lacked the youth team required in order to hold a men's team. FC St. Pauli has 27,000 members as of November 2018.

FC St Pauli has a cross-city rivalry with Hamburger SV; the matches between the two are known as the Hamburger Stadtderby or simply Derby. The club also has a more recent rivalry with Hansa Rostock. Although the footballers have enjoyed only modest success on the field, the club is widely recognised for its distinctive social culture and has a large popular following as one of the country's "Kult" clubs, which has now developed beyond Germany.