Milorg was the main Norwegian resistance movement during World War II. Resistance work included intelligence gathering, sabotage, supply-missions, raids, espionage, transport of goods imported to the country, release of Norwegian prisoners and escort for citizens fleeing the border to neutral Sweden.

The Norwegian resistance to the occupation of Norway by Nazi Germany began after Operation Weserübung in 1940 and ended in 1945. It took several forms:Asserting the legitimacy of the exiled government, and by implication the lack of legitimacy of Vidkun Quisling's pro-Nazi regime and Josef Terboven's military administration The initial defence in Southern Norway, which was largely disorganised, but succeeded in allowing the government to escape capture The more organised military defence and counter-attacks in parts of Western and Northern Norway, aimed at securing strategic positions and the evacuation of the government Armed resistance, in the form of sabotage, commando raids, assassinations and other special operations during the occupation Civil disobedience and unarmed resistance