Vidkun Abraham Lauritz Jonssøn Quisling (, Norwegian: [ˈvɪ̂dkʉn ˈkvɪ̂slɪŋ] (listen); 18 July 1887 – 24 October 1945) was a Norwegian military officer, politician and Nazi collaborator who nominally headed the government of Norway during the country's occupation by Nazi Germany during World War II.

He first came to international prominence as a close collaborator of the explorer Fridtjof Nansen, and through organising humanitarian relief during the Russian famine of 1921 in Povolzhye. He was posted as a Norwegian diplomat to the Soviet Union and for some time also managed British diplomatic affairs there. He returned to Norway in 1929 and served as minister of defence in the governments of Peder Kolstad (1931–32) and Jens Hundseid (1932–33) in representing the Farmers' Party.

In 1933, Quisling left the Farmers' Party and founded the fascist Nasjonal Samling (National Union). Although he gained some popularity after his attacks on the political left, his party failed to win any seats in the Storting, and by 1940, it was still little more than peripheral. On 9 April 1940, with the German invasion of Norway in progress, he attempted to seize power in the world's first radio-broadcast coup d'état but failed since the Germans refused to support his government. From 1942 to 1945, he served as minister president and headed the Norwegian state administration jointly with the German civilian administrator, Josef Terboven. His pro-Nazi puppet government, known as the Quisling regime, was dominated by ministers from Nasjonal Samling. The collaborationist government participated in Germany's war efforts, and sent Jews out of the country to concentration camps in occupied Poland (General Government).

Quisling was put on trial during the legal purge in Norway after World War II. He was found guilty of charges including embezzlement, murder and high treason against the Norwegian state, and was sentenced to death. He was executed by firing squad at Akershus Fortress, Oslo, on 24 October 1945.

Since his death, Quisling has become one of history's most infamous traitors due to his collaboration with Nazi Germany. The term quisling has become a byword for "collaborator" or "traitor" in several languages and reflects the contempt with which Quisling's conduct has been regarded both at the time and in the present day.