Romania–Yugoslavia relations were historical foreign relations between Romania (both Kingdom of Romania 1918-1947 and the People's or Socialist Republic of Romania 1947–1989) and now broken up Yugoslavia (Kingdom of Yugoslavia 1918-1941 and Socialist Federal Republic of Yugoslavia 1945–1992). Relations between Romania and independent South Slavic states (primarily Serbia) developed before creation of Yugoslavia and union of Transylvania with Romania and those relations played prominent role during the Second Balkan War. Relations between the two states were generally friendly and were only occasionally affected by wider alliance policies.