Gate 13, is the name of the ultras group of the Greek multi-sports club Panathinaikos A.O. Officially founded on November 19, 1966, Gate 13 is the oldest supporters' union in Greece. Gate 13 is one of the most powerful ultras group in Europe and has members from all over Greece and Europe, while over the years it has become a part of the club by affecting club decisions and by following the club on all possible occasions.

Panathinaikos Athlitikos Omilos, also known simply as Panathinaikós, is a major Greek multi-sport club based in the City of Athens. Panathinaikos is one of the most successful multi-sport clubs and one of the oldest clubs in Greece. The name "Panathinaikos" was inspired by the ancient work of Isocrates Panathenaicus, where the orator praise the Athenians for their democratic education and their military superiority, which use it for benefit of all Greeks.