Jong Ajax (or Ajax II) is the reserve team of the Dutch club Ajax, based at Sportpark De Toekomst, and has competed in the Eerste Divisie (the second tier of Dutch football) since 2013. It is the only reserve side to have won a professional league title, claiming the 2017–18 Eerste Divisie with a squad featuring Noussair Mazraoui, Noa Lang, and Danilho Doekhi. Under Dutch regulations, the team cannot be promoted to the Eredivisie or enter the KNVB Cup, as its primary purpose is to develop players for Ajax's senior squad. Before joining the Eerste Divisie, Jong Ajax dominated the Beloften Eredivisie (reserve league), winning a record eight titles (1994–2009) and three KNVB Reserve Cups, and even reached the KNVB Cup semi-finals in 2001–02 under Jan Olde Riekerink. The 2013–14 season marked its professional league debut, joining Jong PSV and Jong FC Twente, with player movement between the reserve and first teams now restricted to transfer windows (unless a player has made fewer than 15 first-team appearances). This makes Jong Ajax the most successful reserve squad in the Netherlands, serving as a crucial stepping stone for young talents.