In Dutch sports, The Big Three is the nickname for the three most successful rivalling football clubs in the Netherlands: Ajax from Amsterdam, Feyenoord from Rotterdam and PSV from Eindhoven. Collectively they amounted to 77 of the 134 Dutch Football Championships ever played, and 62 of a possible 70 championships since the introduction of professional football in 1954. The three clubs generally end up sharing the top three positions and contending for the title. None of them has been relegated from the Eredivisie either, having been participants in all editions since Dutch football was merged into a single top-level competition in the 1956–57 season.

Amsterdamsche Football Club Ajax, also known as AFC Ajax, Ajax Amsterdam, or commonly Ajax, is a Dutch professional football club based in Amsterdam, that plays in the Eredivisie, the top tier in Dutch football. Historically, Ajax is the most successful club in the Netherlands, with 36 Eredivisie titles and 20 KNVB Cups. It has continuously played in the Eredivisie since the league's inception in 1956, and along with Feyenoord and PSV Eindhoven, it is one of the country's "big three" clubs that have dominated that competition.