Amsterdamsche Football Club Ajax (Dutch pronunciation: [ˈaːjɑks]), also known as AFC Ajax, Ajax Amsterdam, or simply Ajax, is a Dutch professional football club based in Amsterdam, that plays in the Eredivisie, the top tier in Dutch football.

Historically, Ajax (named after the legendary Greek hero) is the most successful club in the Netherlands, with 36 Eredivisie titles and 20 KNVB Cups.