History of Bosnia and Herzegovina (1941–1945)

Once the kingdom of Yugoslavia was conquered by Nazi forces in World War II, all of Bosnia was ceded to the Nazi-puppet state of Croatia. The Nazi rule over Bosnia led to widespread persecution, murder, and near-total annihilation of the Jewish population, while the NDH Croatian state also specifically persecuted the country's Serbs. Many Serbs themselves took up arms and joined the Chetniks; a Serb nationalist and royalist resistance movement that both conducted guerrilla warfare against the occupying forces and committed numerous atrocities against chiefly Bosnian Muslim civilians in regions under their control.

Starting in 1941, Yugoslav communists under the leadership of Josip Broz Tito organized their own multi-ethnic resistance group, the partisans, who fought against both Axis and Chetnik forces. On November 29, 1943 the Anti-Fascist Council of National Liberation of Yugoslavia with Tito at its helm held a founding conference in Jajce where Bosnia and Herzegovina was reestablished as a republic within the Yugoslavian federation in its Ottoman borders. Military success eventually prompted the Allies to support the Partisans, and the end of the war resulted in the establishment of the Socialist Federal Republic of Yugoslavia, with the constitution of 1946 officially making Bosnia and Herzegovina one of six constituent republics in the new state.