Stephen I Kotromanić (Bosnian: Stjepan Kotromanić/Стјепан Котроманић) (1242–1314) was a Bosnian Ban from 1287 to 1290 jointly with Ban Prijezda II and 1290–1314 alone as a vassal of the Kingdom of Hungary. He is the eponymous founder of the Bosnian ruling dynasty, the House of Kotromanić.