World War II was primarily a conflict between the Allies (the United States, the United Kingdom, France and Russia) and the Axis powers (Germany, Japan and Italy). The Axis also included Bulgaria, Romania and Hungary, while Finland, Thailand and Iraq joined the fight on their side as cobelligerents. The Allies were joined by a host of other countries from around the world that contributed forces or supplies to the fight.
The full list of Allied powers also included Poland, China, Canada, Australia, New Zealand, Yugoslavia, Greece, the Netherlands, Belgium, South Africa, Norway, Czechoslovakia, Ethiopia, Brazil, Denmark, Luxembourg, Cuba and Mexico. In addition, both sides had client states and colonies that were involved in the global struggle.
Certain countries were more active in different theaters of the war. Japan, for instance, was entirely absent from the European theater of war, while the Pacific theater was heavily dominated by the American, Australian and New Zealand forces due to their proximity to Japan's territory. China was largely relegated to a defensive role against Japan's aggression, although the country did serve a vital role supporting air raids over the Japanese mainland. France was caught in the middle of the conflict, with the legitimate government overthrown and the Vichy regime set up in its place to support the Axis. However, the French resistance was an important force throughout the war, and entire villages were razed by the Germans in retribution for their determined refusal to give in.