Besiktas Jimnastik Kulubu is a Turkish multi-sport club from the Besiktas district of Istanbul, tracing its origins to 1903, which makes it the oldest of Turkey's traditional big three. Founded first as a gymnastics society, it added a football branch in the following decade and has never been relegated from the Turkish top flight.

Playing in black and white and known as the Black Eagles, Besiktas have won the Turkish league title on numerous occasions, including sixteen Super Lig championships, together with a long list of Turkish Cup successes. The club's home is the Tupras Stadyumu at Dolmabahce on the shore of the Bosphorus, rebuilt on the site of the old Inonu Stadium and opened in 2016. Matches against Galatasaray and Fenerbahce form the Intercontinental derbies that dominate the Istanbul football calendar.