A large selection of football shirts from FC Schalke 04

Fußballclub Gelsenkirchen-Schalke 04 e. V. is a professional German football and multi-sports club originally from the Schalke district of Gelsenkirchen, North Rhine-Westphalia. The "04" in the club's name derives from its formation in 1904. Schalke have been one of the most popular professional football teams in Germany, even though the club's heyday was in the 1930s and 1940s. Schalke play in the 2. Bundesliga, the second tier of the German football league system, following relegation from the Bundesliga in 2022–23. As of 2023, the club has 176,000 members, making it the second-largest football club in Germany and the fourth-largest club in the world in terms of membership. Other activities offered by the club include athletics, basketball, handball, table tennis, winter sports and eSports.

Schalke have won seven German championships, five DFB-Pokals, one DFB Ligapokal, one DFL-Supercup and one UEFA Cup. In 1937, Schalke became the first German club to win the double. Since 2001, Schalke's stadium has been the Veltins-Arena. Schalke hold a long-standing rivalry with Ruhr neighbours Borussia Dortmund, known as the Revierderby.