The Battle of Vercors in July and August 1944 was between a rural group of the French Forces of the Interior (FFI) [maquis] and the armed forces of Nazi Germany which had occupied France since 1940 in the Second World War. The maquis used the prominent scenic plateau known as the Massif du Vercors as a refuge. The maquis carried out sabotage and partisan operations against the Germans. After the Normandy Invasion of 6 June 1944, the leadership of a force of about 4,000 maquis declared the Free Republic of Vercors and attempted to create a conventional army to oppose the German occupation.

The French Forces of the Interior were French resistance fighters in the later stages of World War II. Charles de Gaulle used it as a formal name for the resistance fighters. The change in designation of these groups to FFI occurred as France's status changed from that of an occupied nation to one of a nation being liberated by the Allied armies. As regions of France were liberated, the FFI were more formally organized into light infantry units and served as a valuable manpower addition to regular Free French forces. In this role, the FFI units manned less active areas of the front lines, allowing regular French army units to practice economy of force measures and mass their troops in decisive areas of the front. Finally, from October 1944 and with the greater part of France liberated, the FFI units were amalgamated into the French regular forces continuing the fight on the Western Front, thus ending the era of the French irregulars in World War II.