1920–21 Serbian Football Championship

The Serbian Football Championship season of 1920–21 was the second championship organised by the Serbian Football Federation (Srpski loptački savez) after the 1919–20 season. Played among the clubs from the territory of the city of Belgrade, the Belgrade Football Subassociation.

Second Leagues
Banat League

Participating:
 * Obilić Veliki Bečkerek
 * Vašaš Veliki Bečkerek
 * Viktorija Veliki Bečkerek
 * ŽSE Žombolj
 * ŽTK Žombolj
 * Šveboše Žombolj
 * DSK Debeljača
 * KAC Velika Kikinda

Provincial League - Župa 1

Participating:
 * Vojvodina Novi Sad
 * NAK Novi Sad
 * NSK Zemun
 * ASK Zemun
 * PSK Pančevo
 * RSK Ruma

Provincial League - Župa 2

Participating:
 * Zora Bijeljina
 * Podrinje Bijeljina
 * Jedinstvo Brčko
 * Sloga Brčko
 * Građanski Sremska Mitrovica
 * Srpski SK Sremska Mitrovica
 * Sloga Šabac
 * Srpski mač Valjevo

Provincial League - Župa 2

Participating:
 * Jedinstvo Vranje
 * Moravac Leskovac
 * Jug Bogdan Prokuplje
 * Zlatibor Užice
 * Šumadija Kragujevac
 * PSK Požarevac