Yugoslav irredentism refers to an irredentism that promotes a Yugoslavia that unites all South Slav-populated territories within it, comprising its historically united territories of Bosnia and Herzegovina, Croatia, Montenegro, Serbia including the disputed territory of Kosovo, Slovenia, and Vardar Macedonia; merged with territories claimed by Yugoslavists that had not been incorporated within the state of Yugoslavia, including Bulgaria, Western Thrace and Greek Macedonia and in some proposals other territories. The government of the Kingdom of Yugoslavia sought the union of Bulgaria into Yugoslavia. The Socialist Federal Republic of Yugoslavia under Josip Broz Tito sought to create an integral Yugoslavia that would incorporate within Yugoslavia's borders: Greek Macedonia and Thrace, Albania, Bulgaria, at least a portion of Austrian Carinthia or all of it, and for a time beginning in November 1943 had claimed the entire Italian region of Friuli-Venezia Giulia.
Proponents of Yugoslav irredentism included both monarchists and republicans. Days prior to Yugoslavia's creation in 1918, Yugoslavist politician Svetozar Pribićević declared that Yugoslavia's borders should extend "from the Soča up to Salonika". Proposals in the interwar period to include Bulgaria within Yugoslavia, included claims by republicans that a republic was necessary for an Integral Yugoslavia with Bulgaria, while others claimed that a republic would not because Bulgaria at that time was a kingdom, and instead claimed that a limited constitutional monarchy would be an appropriate form of state that could include Bulgaria within it. The militant movement Zveno in Bulgaria supported an Integral Yugoslavia that included Bulgaria as well as Albania within it. The Zveno movement participated in the Bulgarian coup d'état of 1934, the coup supporters declared their intention to immediately form an alliance with France and to seek the unification of Bulgaria into an Integral Yugoslavia.
Once World War II began, in 1940 General Milan Nedić proposed that Yugoslavia join the Axis Powers and attack Greece to seize Salonika. During World War II, the British government supported the creation of a Greater Yugoslavia after the war due to opposition to the Bulgarian government's accession to the Axis Powers, in May 1941 endorsing Dr. Malcom Burr's paper in favour of the incorporation of Bulgaria into Yugoslavia after the war.
After World War II, Tito declared that Yugoslavia had the right to have Trieste and all of Carinthia, including Austrian Carinthia, saying "We have liberated Carinthia but international conditions were such that we had to leave it temporarily. Carinthia is ours and we shall fight for it".
- Cecil Frank Melville. Balkan racket: the inside story of the political gangster plot which destroyed Yugoslavia and drove Britain out of the Balkans. Jarrold, 1941. Pp. 61.
- Ramet 2006, p. 172.
- Near East and India , Volume 44. University of Minnesota, 1935. Pp. 4 and 149.
- Ivo Banač. The national question in Yugoslavia: origins, history, politics. Cornell University Press, 1984. Pp. 128.
- Near East and India , Volume 44. University of Minnesota, 1935. Pp. 149.
- Plamen S. T︠S︡vetkov. A history of the Balkans: a regional overview from a Bulgarian perspective. EM Text, 1993. Pp. 195.
- Khristo Angelov Khristov. Bulgaria, 1300 years. Sofia, Bulgaria: Sofia Press, 1980. Pp. 192.
- John R. Lampe. Yugoslavia As History: Twice There Was a Country. Cambridge, England, UK: Cambridge University Press, 2000. Pp. 199.
- Dimitris Livanios. The Macedonian question: Britain and the southern Balkans: 1939-1949. Oxford, England, UK: Oxford University Press, 2008 Pp. 103.
- Ramet 2006, pp. 172-173.
- Ramet, Sabrina P. (2006). The three Yugoslavias: state-building and legitimation, 1918-2005. Bloomington, Indiana, USA: Indiana University Press.