The Allied occupation of Austria started on 27 April 1945 as a result of the Vienna Offensive and ended with the Austrian State Treaty on 27 July 1955.

Subsequent to the Anschluss in 1938, Austria had generally been recognized as a constituent part of Nazi Germany. In 1943 however, the Allies agreed in the Declaration of Moscow that Austria would instead be regarded as the first victim of Nazi aggression, and treated as a liberated and independent country after the war.

In the immediate aftermath of World War II, Austria was divided into four occupation zones and jointly occupied by the United States, the Soviet Union, the United Kingdom, and France. Vienna was similarly subdivided but the central district was collectively administered by the Allied Control Council.

Whereas Germany was divided into East and West Germany in 1949, Austria remained under joint occupation of the Western Allies and the Soviet Union until 1955; its status became a controversial subject in the Cold War until the warming of relations known as the Khrushchev Thaw. After Austrian promises of perpetual neutrality, Austria was accorded full independence on 15 May 1955 and the last occupation troops left on 25 October that year.