Milorg (abbreviation of militær organisasjon - military organization) was the main Norwegian resistance movement in 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.

Following the German occupation in April 1940, Milorg was formed in May 1941 as a way of organizing the various groups that wanted to participate in an internal military resistance. At first, Milorg was not well coordinated with the Special Operations Executive (SOE), the British organization to plan and lead resistance in occupied countries. In November 1941 the Milorg became integrated with the High Command of the Norwegian government in exile in London, answering to Department FO. IV, which dealt with sabotage operations, but its British counterpart, SOE, was still operating independently. This lack of coordination led to a number of tragic incidents, creating bitterness within Milorg. SOE changed its policy at the end of 1942, and from then on Milorg and SOE efforts were coordinated.

Milorg was organised into a council and 14 districts. District 13 was the Oslo region. Mainly for fear of retaliation, like the Telavåg tragedy, Milorg kept a low profile at first. But they became more active as the war progressed, especially when Jens Christian Hauge became leader of Milorg. At the time of the German capitulation on 8 May 1945, Milorg had been able to train and supply 40,000 soldiers. They also played an important part in stabilizing the country at this crucial point.