The Norwegian resistance (Norwegian: Motstandsbevegelsen) 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
Asserting legitimacy of exiled Norwegian government
The Norwegian government of Prime Minister Johan Nygaardsvold, with the exception of foreign minister Halvdan Koht and minister of defence Birger Ljungberg, was largely caught by surprise when it became apparent in the early hours of 9 April 1940 that Nazi Germany had launched an invasion of Norway. Although some of the country's gold reserve had already been removed from Oslo, there were few contingency plans for such an invasion.
The Norwegian government was unprepared and unwilling to capitulate to the ultimatum timed to coincide with the arrival of German troops and delivered by Curt Bräuer, the German representative in Oslo. The German demand that Norway accept the "protection of the Reich" was rebuffed by Koht and the Norwegian government before dawn had broken on the morning of invasion. "Vi gir oss ikke frivillig, kampen er allerede i gang", replied Koht. "We will not submit voluntarily; the fight is already underway."
Anticipating German efforts to capture the government, the entire Norwegian parliament (the Storting), the royal family, and cabinet hastily evacuated Oslo by train and car to Hamar and then on to Elverum, where an extraordinary session of parliament was called. In large part because of the presence of mind of the parliament's president C. J. Hambro, the Storting managed to pass an emergency measure (known as the Elverum Authorization) that gave full authority to the king and his cabinet until the Storting could convene again.
This gave King Haakon VII and the cabinet constitutional authority to reject the German emissary's ultimatum to accept the German invasion. Although there were several German attempts to capture or kill the King and the Norwegian government, they managed to evade these attempts and travelled through Norway's remote interior until leaving the country for London on the British heavy cruiser HMS Devonshire on 7 June.
Reserving the constitutional legitimacy of the Norwegian government also undermined Vidkun Quisling's attempts at claiming the Norwegian government for himself. After Quisling had proclaimed his assumption of the government, several individuals on the Supreme Court took the initiative to establish an Administrative Council (Administrasjonsrådet) in an effort to stop him. This became a controversial initiative, in that the legitimate Norwegian government refused to give the council any legal backing, and the German authorities ended up disbanding it.
Although some politicians across the political spectrum had advocated strengthening the country's defence capabilities, a longstanding policy of disarmament following World War I had left the Norwegian military underfunded and undertrained by the late 1930s. As a result, forces in Southern Norway were largely unprepared for the German invasion, and the invading German army met little initial resistance.
There was also spirited defence seen at other locations, including Midtskogen, Hegra and Narvik but these were largely the result of improvised missions by isolated military units and irregular volunteers. The battles slowed the German advance by several days, allowing the Norwegian government to evade capture and conduct critical constitutional business.
The British and French began landing on Norwegian soil within a week of the German invasion.
Several Norwegian military units that had mobilised as a precautionary measure in Northern Norway during the Winter War, in cooperation with Polish, French and British forces, launched several counterattacks with moderate success. Allied forces had several successes in Northern Norway, but were redirected for the futile defense of France. While Northern Norway ultimately fell, efforts there allowed the Norwegian government, including the Norwegian royal family, to escape and maintain the legitimate government in exile, as part of the Allies.
While on station in London, the government contributed to Norwegian forces with the Allied effort and ordered the Norwegian Merchant Fleet to assist in troop transportation. To expedite this ships operated under the Nortraship organisation, which at that time was the world's largest shipping company. It created apprehension among the Nazi leadership that Allied forces might try to recapture Norway with the intention of denying German naval units access to the North Atlantic, tying up several hundred thousand troops that otherwise might have been deployed to other fronts.
Although Norway did not have any major battles beyond those of the Norwegian campaign, a number of military operations served to subvert the Nazi authorities and contribute to the larger war effort. Milorg started out as a small sabotage unit and ended up building a full military force in time for the liberation. Company Linge was a special operations (SOE) unit that specialised in coastal insertions and combat. There were repeated raids in Lofoten, Måløy, and other coastal areas.