Yugoslavia (; lit. 'Land of the South Slavs') was a country in Central Europe and the Balkans that existed from 1918 to 1992. It came into existence following World War I, under the name of the Kingdom of Serbs, Croats and Slovenes from the merger of the Kingdom of Serbia with the provisional State of Slovenes, Croats and Serbs, and constituted the first union of South Slavic peoples as a sovereign state, following centuries of foreign rule over the region under the Ottoman Empire and the Habsburg monarchy.

Under the rule of the House of Karađorđević, the kingdom gained international recognition on 13 July 1922 at the Conference of Ambassadors in Paris and was renamed the Kingdom of Yugoslavia on 3 October 1929. Peter I was the country's first sovereign. Upon his father's death in 1921, Alexander I went on to rule the country through an extended period of political crisis that culminated in the 6 January Dictatorship and, ultimately, his assassination in 1934. Prince Paul headed the state as a prince regent until Alexander's son Peter II was declared of-age, which happened following the Yugoslav coup d'état in March 1941. Alexander I was the longest reigning of the three Yugoslav monarchs.

The kingdom was invaded and occupied by the Axis powers in April 1941, marking the start of World War II in Yugoslavia. The Communist-led Partisan resistance went on to proclaim the Democratic Federal Yugoslavia in November 1943, having acquired the backing of the Allies earlier that year. In 1944, King Peter II, then living in exile, gave his recognition to the Anti-Fascist Council for the National Liberation of Yugoslavia as the legitimate government.