The Belgian Resistance (French: Résistance belge, Dutch: Belgisch verzet) collectively refers to the resistance movements opposed to the German occupation of Belgium during World War II. Within Belgium, resistance was fragmented between a large number of separate organizations, divided by region and political stances. The resistance included both men and women from both Walloon and Flemish parts of the country. Aside from sabotage of military infrastructure in the country and assassinations of collaborators, these groups also published large numbers of underground newspapers, gathered intelligence and maintained various escape networks that helped Allied airmen trapped behind enemy lines escape from German-occupied Europe.
During the war, it is estimated that approximately five percent of the national population were involved in some form of resistance activity, while some estimates put the number of resistance members killed at over 19,000; roughly 25 percent of its "active" members.
German forces invaded Belgium, which had been following a policy of neutrality, on 10 May 1940. After 18 days of fighting, Belgium surrendered on 28 May and was placed under German occupation. During the fighting, between 600,000 and 650,000 Belgian men (nearly 20 percent of the country's entire male population) served in the military. Many were made prisoners of war and detained in camps in Germany, although some were released before the end of the war. Leopold III, king and commander-in-chief of the army, also surrendered to the Germans on 28 May along with his army and was also held as prisoner by the Germans. The Belgian government fled first to Bordeaux in France, and then to London where it formed a government in exile.