Genk U21

Two clubs from the Genk area, KFC Winterslag, formed in 1923, and K Waterschei SV Thor Genk, formed in 1919, gave up their separate existences in 1988 to become one. The blue-and-white side they created took the nickname The Smurfs, and its reserve team, Jong Genk, carries the same name and colours. It has no legal founding date or registration number of its own, because it is part of the parent club.

Since the 2023/24 season the reserves have not played in the city at all. They left the Cegeka Arena, formerly the Luminus Arena, which holds 23,718, and now play their Challenger Pro League home games at the Leunenstadion in Geel, which holds roughly 8,000 to 10,500.

Genk's academy has produced Kevin De Bruyne, Thibaut Courtois, Yannick Carrasco, Dennis Praet and Divock Origi. Two more recent departures are Mika Godts, who went to Ajax, and Lucca Brughmans, who went to Liverpool. It enters the Premier League International Cup alongside other European reserve sides. The senior team has won four league titles and six Belgian Cups, and the reserves have won none of those.