Serbia and Montenegro, union of the republics of Serbia and Montenegro, located in southeastern Europe on the Balkan Peninsula. The republic of Serbia is much larger and more populous than Montenegro, and it is home to the capital and largest city, Belgrade.

From 1945 to 1991 Serbia and Montenegro was part of Yugoslavia, a larger Communist federal state consisting of six republics. Yugoslavia’s named changed to the Socialist Federal Republic of Yugoslavia (SFRY) in 1963. In 1990 the Communist Party collapsed, and new non-Communist parties formed. Multiparty elections that year ended 45 years of one-party rule but also brought nationalist political parties into power in all six republics, contributing to ethnic tension in the SFRY. Four of the republics—Bosnia and Herzegovina, Croatia, Macedonia, and Slovenia—declared their independence in 1991 and 1992, leaving only Serbia and Montenegro unified. The SFRY’s dissolution led to a series of armed conflicts known as the wars of Yugoslav succession.