The Kingdom of Yugoslavia (Serbo-Croatian: Kraljevina Jugoslavija / Краљевина Југославија;[8] Slovene: Kraljevina Jugoslavija) was a state in Southeast and Central Europe that existed from 1918 until 1941. From 1918 to 1929, it was officially called the Kingdom of Serbs, Croats, and Slovenes (Serbo-Croatian: Kraljevina Srba, Hrvata i Slovenaca / Краљевина Срба, Хрвата и Словенаца; Slovene: Kraljevina Srbov, Hrvatov in Slovencev), but the term "Yugoslavia" (lit. 'Land of the South Slavs') was its colloquial name due to its origins.[9] The official name of the state was changed to "Kingdom of Yugoslavia" by King Alexander I on 3 October 1929.[9]

The preliminary kingdom was formed in 1918 by the merger of the provisional State of Slovenes, Croats and Serbs (itself formed from territories of the former Austria-Hungary, encompassing today's Bosnia and Herzegovina and most of today's Croatia and Slovenia) and Banat, Bačka and Baranja (that had been part of the Kingdom of Hungary within Austria-Hungary) with the formerly independent Kingdom of Serbia. In the same year, the Kingdom of Montenegro also proclaimed its unification with Serbia, whereas the regions of Kosovo and Vardar Macedonia had become parts of Serbia prior to the unification.[10]

The state was ruled by the Serbian dynasty of Karađorđević, which previously ruled the Kingdom of Serbia under Peter I from 1903 (after the May Coup) onward. Peter I became the first king of Yugoslavia until his death in 1921. He was succeeded by his son Alexander I, who had been regent for his father. He was known as "Alexander the Unifier" and he renamed the kingdom "Yugoslavia" in 1929. He was assassinated in Marseille by Vlado Chernozemski, a member of the Internal Macedonian Revolutionary Organization (IMRO), during his visit to France in 1934. The crown passed to his 11-year-old son, Peter. Alexander's cousin Paul ruled as Prince regent until 1941, when Peter II came of age.[11] The royal family flew to London the same year, prior to the country being invaded by the Axis powers.

In April 1941, the country was occupied and partitioned by the Axis powers. A royal government-in-exile, recognized by the United Kingdom and, later, by all the Allies, was established in London. In 1944, after pressure from the British Prime Minister Winston Churchill, the King recognized the government of Democratic Federal Yugoslavia as the legitimate government. This was established on 2 November following the signing of the Treaty of Vis by Ivan Šubašić (on behalf of the Kingdom) and Josip Broz Tito (on behalf of the Yugoslav Partisans).[12]

Democratic Federal Yugoslavia, also known as Democratic Federative Yugoslavia (DF Yugoslavia or DFY), was a provisional state established during World War II on 29 November 1942 through the Second Session of the Anti-Fascist Council for the National Liberation of Yugoslavia (AVNOJ). The National Committee for the Liberation of Yugoslavia (NKOJ) was its original executive body. Throughout its existence it was governed by Marshal Josip Broz Tito as prime minister.

It was recognized by the Allies at the Tehran Conference, along with the AVNOJ as its deliberative body. The Yugoslav government-in-exile of King Peter II in London, partly due to pressure from the United Kingdom,[3] recognized the AVNOJ government with the Treaty of Vis, signed on 16 June 1944 between the prime minister of the government-in-exile, Ivan Šubašić, and Tito.[3] With the Treaty of Vis, the government-in-exile and the NKOJ agreed to merge into a provisional government as soon as possible. The form of the new government was agreed upon in a second Tito–Šubašić agreement signed on 1 November 1944 in the recently liberated Yugoslav capital of Belgrade. DF Yugoslavia became one of the founding members of the United Nations upon the signing of the United Nations Charter in October 1945.

The state was formed to unite the Yugoslav resistance movement to the occupation of Yugoslavia by the Axis powers. The agreement left the issue of whether the state would be a monarchy or a republic intentionally undecided until after the war had ended so the position of head of state was vacant. After the merger of the governments, the state was reformed as a one-party Federal People's Republic of Yugoslavia with Josip Broz Tito as Prime Minister and Ivan Šubašić as minister of foreign affairs.

The Socialist Federal Republic of Yugoslavia (SFRY), commonly referred to as SFR Yugoslavia or simply as Yugoslavia, was a country in Central and Southeast Europe. It emerged in 1945, following World War II, and lasted until 1992, with the breakup of Yugoslavia occurring as a consequence of the Yugoslav Wars. Spanning an area of 255,804 square kilometres (98,766 sq mi) in the Balkans, Yugoslavia was bordered by the Adriatic Sea and Italy to the west, by Austria and Hungary to the north, by Bulgaria and Romania to the east, and by Albania and Greece to the south. It was a one-party socialist state and federation governed by the League of Communists of Yugoslavia, and had six constituent republics: Bosnia and Herzegovina, Croatia, Macedonia, Montenegro, Serbia, and Slovenia. Within Serbia was the Yugoslav capital city of Belgrade as well as two autonomous Yugoslav provinces: Kosovo and Vojvodina.

The SFR Yugoslavia 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.[9][10] 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 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 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 sole successor state to SFR Yugoslavia. "Former Yugoslavia" is now commonly used retrospectively.

Serbia and Montenegro (Serbian: Cрбија и Црна Гора, romanized: Srbija i Crna Gora), known until 2003 as the Federal Republic of Yugoslavia (Serbian: Савезна Република Југославија), FR Yugoslavia or simply Yugoslavia (Serbian: Југославија), was a country in Southeast Europe located in the Balkans that existed from 1992 to 2006, following the breakup of the Socialist Federal Republic of Yugoslavia (SFR Yugoslavia). The country bordered Hungary to the north, Romania to the northeast, Bulgaria to the southeast, North Macedonia to the south, Croatia and Bosnia and Herzegovina to the west, and Albania to the southwest. The state was founded on 27 April 1992 as a federation comprising the Republic of Serbia and the Republic of Montenegro. In February 2003, it was transformed from a federal republic to a political union until Montenegro seceded from the union in June 2006, leading to the full independence of both Serbia and Montenegro.

Its aspirations to be the sole legal successor state to SFR Yugoslavia were not recognized by the United Nations, following the passing of United Nations Security Council Resolution 777,[3] which affirmed that the Socialist Federal Republic of Yugoslavia had ceased to exist, and the Federal Republic of Yugoslavia was a new state. All former republics were entitled to state succession while none of them continued SFR Yugoslavia's international legal personality. However, the government of Slobodan Milošević opposed any such claims, and as such, FR Yugoslavia was not allowed to join the United Nations.

Throughout its existence, FR Yugoslavia had a tense relationship with the international community, as economic sanctions[4] were issued against the state during the course of the Yugoslav Wars and Kosovo War. This also resulted in hyperinflation between 1992 and 1994.[5] FR Yugoslavia's involvement in the Yugoslav Wars ended with the Dayton Agreement, which recognized the independence of the Republics of Croatia, Slovenia, and Bosnia and Herzegovina, as well as establishing diplomatic relationships between the states, and a guaranteed role of the Serbian population within Bosnian politics.[6] Later on, growing separatism within the Autonomous Province of Kosovo and Metohija, a region of Serbia heavily populated by ethnic Albanians, resulted in an insurrection by the Kosovo Liberation Army, an Albanian separatist group.[7][8] The outbreak of the Kosovo War reintroduced Western sanctions, as well as eventual Western involvement in the conflict. The conflict ended with the adoption of United Nations Security Council Resolution 1244, which guaranteed economic and political separation of Kosovo from FR Yugoslavia, to be placed under UN Administration.[9]

Economic hardship and war resulted in growing discontent with the government of Slobodan Milošević and his allies, who ran both Serbia and Montenegro as an effective dictatorship.[10] This would eventually cumulate in the Bulldozer revolution, which saw his government overthrown, and replaced by one led by the Democratic Opposition of Serbia and Vojislav Koštunica, which also joined the UN.[11][12]

The Federal Republic of Yugoslavia ended in 2003 after the Federal Assembly of Yugoslavia voted to enact the Constitutional Charter of Serbia and Montenegro, which established the State Union of Serbia and Montenegro. As such, the name Yugoslavia was consigned to history.[13] A growing independence movement in Montenegro, led by Milo Đukanović[14] meant that the Constitution of Serbia and Montenegro included a clause allowing for a referendum on the question of Montenegrin independence,[15] after a period of three years had passed. In 2006, the referendum was called, and passed,[16] by a narrow margin. This led to the dissolution of the State Union of Serbia and Montenegro, and the establishment of the independent republics of Serbia and Montenegro, turning Serbia into a landlocked country. This can be considered the last act which finalized the dissolution of Yugoslavia.[17]