The Belgian Government in London (Dutch: Belgische regering in Londen; French: Gouvernement belge à Londres), also known as the Pierlot IV Government, was the government in exile of Belgium between October 1940 and September 1944 during World War II. The government was tripartite, involving ministers from the Catholic, Liberal and Labour Parties. After the invasion of Belgium by Nazi Germany in May 1940, the Belgian government, under Prime Minister Hubert Pierlot, fled first to Bordeaux in France and then to London, where it established itself as the only legitimate representation of Belgium to the Allies.
Despite no longer having authority in its own country, the government administered the Belgian Congo and held negotiations with other Allied powers about post-war reconstruction. Agreements made by the government in exile during the war included the foundation of the Benelux Customs Union and Belgium's admission into the United Nations. The government also exercised influence within the Belgian army-in-exile and attempted to maintain links with the underground resistance.