The South Slavs constitute the southern ethnographical branch of the Slavic peoples; a group of related ethnic groups that speak South Slavic languages, native to the Balkan peninsula, southern Pannonian Plain and eastern Alps. They number close to 40 million, and include the Bulgarians, Serbs, Croats, ethnic Macedonians, Slovenes, Bosniaks, Montenegrins, including some miniature ethnic groups. They are the main population of the Central- and Southern European countries of Bulgaria, Bosnia and Herzegovina, Croatia, Republic of Macedonia, Montenegro, Serbia and Slovenia. Their territories are separated from the rest of the Slavic nations since the 15th century by the modern non-Slavic states of Austria, Hungary and Romania, leading to a differing historical progression for the South Slav nations in relation to the West- and East Slavs.

Little is known about the Slavs before the 5th century. Their history prior to this can only be tentatively hypothesized via archeological and linguistic studies. Much of what we know about their history after the 6th century is from the works of Byzantine historians.