The General Government, formally the General Governorate for the Occupied Polish Region, was a German zone of occupation established after the invasion of Poland by Nazi Germany, Slovakia and the Soviet Union in 1939 at the onset of World War II. The newly occupied Second Polish Republic was split into three zones: the General Government in its centre, Polish areas annexed by Nazi Germany in the west, and Polish areas annexed by the Soviet Union in the east. The territory was expanded substantially in 1941, after the German Invasion of the Soviet Union, to include the new District of Galicia. The area of the Generalgouvernement roughly corresponded with the Austrian part of the Polish–Lithuanian Commonwealth after the Third Partition of Poland in 1795.

The Invasion of Poland, also known as the September Campaign, Polish Campaign, War of Poland of 1939, and Polish Defensive War of 1939, was a joint attack on the Republic of Poland by Nazi Germany, the Slovak Republic, and the Soviet Union; which marked the beginning of World War II. The German invasion began on 1 September 1939, one week after the signing of the Molotov–Ribbentrop Pact between Germany and the Soviet Union, and one day after the Supreme Soviet of the Soviet Union had approved the pact. The Soviets invaded Poland on 17 September. The campaign ended on 6 October with Germany and the Soviet Union dividing and annexing the whole of Poland under the terms of the German–Soviet Frontier Treaty. The invasion is also known in Poland as the September campaign or 1939 defensive war and known in Germany as the Poland campaign.