World War II by country World War II by country Nearly every country and territory in the world participated in World War II, with the exception of only a few nations which remained neutral. The Second World War pitted two alliances against each other, the Axis powers and the Allied powers. The leading Axis powers were Nazi Germany, the Kingdom of Italy and the Empire of Japan; while the United Kingdom, the United States, the Soviet Union and China were the "Big Four" Allied powers. The countries involved in or affected by World War II are listed here alphabetically, with a description of their role
Allied war crimes during World War II Allied personnel were investigated by the Allied powers and led in some instances to courts-martial. Some incidents alleged by historians to have been crimes under the law of war in operation at the time were, for a variety of reasons, not investigated by the Allied powers during the war, or were investigated and a decision was taken not to prosecute. The Western Allies claim that their militaries were directed to observe the Hague Conventions and Geneva Conventions and believed to be conducting a just war fought for defensive reasons. Violations of the conventions did occur, however, including the forcible return