The Carinthian plebiscite determines that the larger part of the Duchy of Carinthia should remain part of Austria.

The Carinthian plebiscite was held on 10 October 1920 in the area in southern Carinthia predominantly settled by Carinthian Slovenes. It determined the final border between the Republic of Austria and the newly formed Kingdom of Serbs, Croats and Slovenes (Yugoslavia) after World War I. The predominantly Slovene-speaking plebiscite area voted to remain part of Austria with a 59% majority.

The Duchy of Carinthia was a duchy located in southern Austria and parts of northern Slovenia. It was separated from the Duchy of Bavaria in 976, and was the first newly created Imperial State after the original German stem duchies.

The First Austrian Republic, officially the Republic of Austria, was created after the signing of the Treaty of Saint-Germain-en-Laye on 10 September 1919—the settlement after the end of World War I which ended the Habsburg rump state of Republic of German-Austria—and ended with the establishment of the authoritarian Federal State of Austria based upon a dictatorship of Engelbert Dollfuss and the Fatherland Front in 1934. The Republic's constitution was enacted on 1 October 1920 and amended on 7 December 1929. The republican period was increasingly marked by violent strife between those with left-wing and right-wing views, leading to the July Revolt of 1927 and the Austrian Civil War of 1934.