Twelve participating teams for the 2021/21 U19 ABA League Championship - Borac, Cedevita Olimpija, Cibona, Igokea, Krka, Mega Mozzart, Mornar-Barsko zlato, Partizan NIS, SC Derby, Spars, Split and Zadar - will be divided into two first stage groups.
In Group A in Bar, Borac, Cedevita Olimpija, Cibona, Mega Mozzart, Mornar-Barsko zlato and Spars will compete.
In Group B in Laktaši, Igokea, Krka, Partizan NIS, SC Derby, Split and Zadar are set to participate.
In the first stage, all teams will face each other team within a group in a round-robin system. The two best placed teams of each group will advance to the final tournament.
At the final tournament, the teams will play two games – the semifinal and the final or third place game. The winner of the final tournament will become the champion of the 2021/22 U19 ABA League Championship.