Galatasaray Spor Kulübü (Turkish pronunciation: [galataˈsaɾaj spoɾ kuˈlyby], Galatasaray Sports Club), more commonly referred to as simply Galatasaray, is a Turkish professional football club based on the European side of the city of Istanbul. It is the association football branch of the larger Galatasaray Sports Club of the same name, itself a part of the Galatasaray Community Cooperation Committee which includes Galatasaray High School where the football club was founded in October 1905 consisting entirely of student members. The team traditionally play in dark shades of red and yellow at home, with the shirts split down the middle between the two colours.

Galatasaray is one of three teams to have participated in all seasons of the Süper Lig since 1959, following the dissolution of the Istanbul Football League.

Galatasaray also has the most Süper Lig (25), Turkish Cup (19) and Turkish Super Cup (17) titles in Turkey, thus making them the most successful football club in Turkey, as those competitions are the top nationwide Turkish professional leagues and cups that are recognized and accounted for in accordance to the regulations set by the Turkish Football Federation and UEFA.

Galatasaray is also the most successful Turkish club in European competitions. Internationally, Galatasaray has won the UEFA Cup and UEFA Super Cup in 2000, becoming the first and only Turkish team to win a major UEFA competition. In the 1999–2000 season, the club achieved the rare feat of completing a treble by winning the Süper Lig, the Turkish Cup, and the UEFA Cup in a single season. Despite having reached several times the quarter-finals and also once the semi-finals of the UEFA Champions League campaign, the club has not won the trophy so far. Galatasaray is also the only Turkish club to have been ranked first on the IFFHS World Rankings. According to the same international organization, Galatasaray is the best Turkish club of the 20th century, and the 20th most successful club in Europe. Galatasaray is the 11th most participated team in the Champions League, the 18th team to play the most matches and the 24th team to collect the most points.

Since 2011, the club's stadium has been the 53,798-capacity Rams Park in Seyrantepe, Istanbul. Previously, the club played at the Ali Sami Yen Stadium, as well as a succession of other grounds in Istanbul, which included groundshares with Beşiktaş and Fenerbahçe at the Taksim Stadium and İnönü Stadium.

The club has a long-standing rivalry with other Istanbul teams, namely with Beşiktaş and Fenerbahçe. The derby between Galatasaray and Fenerbahçe is dubbed the Kıtalar Arası Derbi (English: Intercontinental Derby) due to the location of their headquarters and stadiums on the European (Galatasaray) and Asian (Fenerbahçe) sides of the Bosphorus strait in Istanbul.