The Norwegian Resistance Movement was a collective effort by Norwegians to oppose the German occupation of Norway during World War II, which began in 1940. This movement included various groups and individuals who engaged in sabotage, intelligence gathering, and promoting anti-Nazi sentiments among the population. Key organizations within the movement included Milorg, which focused on military resistance, and XU, responsible for intelligence operations. The resistance played a crucial role in undermining German control and contributed to the overall Allied efforts in Europe, culminating in the liberation of Norway in 1945.