Yugoslavia's new constitution, modeling that of the Soviet Union, establishes six constituent republics (Bosnia and Herzegovina, Croatia, Macedonia, Montenegro, Serbia and Slovenia).

The 1946 Yugoslav Constitution, officially titled as the Constitution of the Federal People's Republic of Yugoslavia (Serbian: ; Croatian: Ustav Federativne Narodne Republike Jugoslavije), was the first constitution of the Federal People's Republic of Yugoslavia. It was adopted by the Constitutional Assembly of Yugoslavia, elected on 11 November 1945. Constitution came into effect at its promulgation, on 31 January 1946.

The Socialist Federal Republic of Yugoslavia, commonly referred to as SFR Yugoslavia or simply Yugoslavia, was a socialist country in Southeast and Central Europe that existed from its foundation in the aftermath of World War II until its dissolution in 1992 amid the Yugoslav Wars. Covering an area of 255,804 km2 (98,766 sq mi), the SFRY bordered the Adriatic Sea and Italy to the west, Austria and Hungary to the north, Bulgaria and Romania to the east, and Albania and Greece to the south. It was a one-party socialist state and federation governed by the League of Communists of Yugoslavia and made up of six socialist republics—Bosnia and Herzegovina, Croatia, Macedonia, Montenegro, Serbia, and Slovenia—with Belgrade as its capital; it also included two autonomous provinces within Serbia: Kosovo and Vojvodina.

The SFRY traces its origins to 26 November 1942, when the Anti-Fascist Council for the National Liberation of Yugoslavia was formed during World War II to resist Axis occupation of the Kingdom of Yugoslavia. Following the country's liberation, King Peter II was deposed, the monarchy was ended, and on 29 November 1945 the Federal People's Republic of Yugoslavia was proclaimed. Led by Josip Broz Tito, the new Communist government sided with the Eastern Bloc at the beginning of the Cold War but pursued a policy of neutrality following the Tito–Stalin split in 1948; it became one of the founding members of the Non-Aligned Movement, and transitioned from a command economy to market-based socialism.

Following the death of Tito on 4 May 1980, the Yugoslav economy started to collapse, which increased unemployment and inflation. The economic crisis led to rising ethnic nationalism and political dissidence in the late 1980s and early 1990s. With the fall of communism in Eastern Europe, efforts to transition into a confederation also failed; the two wealthiest republics, Croatia and Slovenia, seceded and gained some international recognition in 1991. The federation dissolved along the borders of federated republics, hastened by the start of the Yugoslav Wars, and the federation formally broke up on 27 April 1992. Two republics, Serbia and Montenegro, remained within a reconstituted state known as the Federal Republic of Yugoslavia, or FR Yugoslavia, but this state was not recognized internationally as the official successor state to SFR Yugoslavia. Former Yugoslavia is now commonly used retrospectively.