In WWII it was all the commonwealth countries (UK, Canada, Australia, New Zealand, South Africa), USA (from 1941) and China. The following countries were nominally Allied but were occupied early on in the war and only elements of their military forces continued to fight, usually under the command of other Allied armies: France, Poland, Greece. The following countries switched sides in the conflict as the war turned against the Axis powers: Romania, Bulgaria, Italy. Many other colonies and client states in Africa and Asia also took part, but not as independent Allied nations. India falls in this category. The Soviet Union (USSR) was never formally a member of the Allies, but fought on their side from 1941, following the Axis invasion of the USSR.