The German occupation of Luxembourg in World War II began in May 1940 after the Grand-Duchy of Luxembourg was invaded by Nazi Germany. Although Luxembourg was officially neutral, it was situated at a strategic point at the end of the French Maginot Line. On 10 May 1940, the German Wehrmacht invaded Luxembourg, Belgium and the Netherlands. Luxembourg was initially placed under a Military administration, but later became a civilly administrated territory and finally was annexed directly into Germany. The Germans believed Luxembourg to be a Germanic state, and attempted to suppress what they perceived as alien French language and cultural influences. Although some Luxembourgers joined the resistance or collaborated with the Germans, both constituted a minority of the population. As German nationals, from 1942, many Luxembourgers were conscripted into the German military. Nearly 3,500 Luxembourgish Jews were killed during the Holocaust. The liberation of the country by the Allies began in September 1944, but due to the Ardennes Offensive it wasn't completed until early 1945.
The outbreak of World War II on 1 September 1939 put Luxembourg’s government in a delicate situation. On the one hand, the population’s sympathy lay with Belgium and France; on the other hand, due to the country's policy of neutrality since 1867's Treaty of London, the government adopted a careful non-belligerent stance towards its neighbours. As of 1 September, Radio Luxembourg stopped broadcasting. In spring 1940, fortifications were erected along the borders with Germany and France. The so-called Schuster Line, named after its constructor, consisted of massive concrete roadblocks with steel doors. The official aim of these road blocks was to slow down the progress of any invading army and give time for the guarantors of Luxembourg's neutrality to take counteractions against the invaders. However, compared to the massive power of the German forces, it only had symbolic character and helped to calm down the population. Except for its small Corps des Gendarmes et Volontaires, Luxembourg did not possess an army, due to the treaty's restrictions.