Bulgaria–Yugoslavia relations

Bulgaria–Yugoslavia relations were historical foreign relations between Bulgaria (both Kingdom of Bulgaria 1908–1946 and the People's Republic of Bulgaria 1946–1990) and now broken up Yugoslavia (Kingdom of Yugoslavia 1918–1941 and Socialist Federal Republic of Yugoslavia 1945–1992). Despite some substantial unification proposals in the aftermath of the World War II, Bulgarians were the only South Slavic nation which did not join the Yugoslav (lit. 'South Slav') federation.