The Office of Military Government, United States was the United States military-established government created shortly after the end of hostilities in occupied Germany in World War II. Under General Lucius D. Clay, it administered the area of Germany and sector of Berlin controlled by the United States Army. The Allied Control Council comprised military authorities from the United States, the United Kingdom, the Soviet Union and France. Though created on January 1, 1946, OMGUS previously reported to the U.S. Group Control Council, Germany (USGCC), which existed from May 8, 1945, until October 1, 1945. OMGUS was eliminated on December 5, 1949, and the U.S. High Commissioner for Germany assumed control of its functions.

The entirety of Germany was occupied and administered by the Allies of World War II from the Berlin Declaration on 5 June 1945 to the establishment of West Germany on 23 May 1949. Unlike occupied Japan, Germany was stripped of its sovereignty and former state: after Nazi Germany surrendered on 8 May 1945, four countries representing the Allies asserted joint authority and sovereignty through the Allied Control Council (ACC). At first, Allied-occupied Germany was defined as all territories of Germany before the 1938 Nazi annexation of Austria; the Potsdam Agreement on 2 August 1945 defined the new eastern German border by giving Poland and the Soviet Union all regions of Germany east of the Oder–Neisse line and divided the remaining "Germany as a whole" into four occupation zones, each administered by one of the Allies.