The Axis

• German
• Italy
• Japan

Slovakia (Nov. 1940)
Hungary (Nov. 1940)
Romania (Nov. 1940)
Bulgaria (March 1941)

The Allies

• Australia
• Belgium
• Brazil
• Canada
• China
• Czechoslovakia
• Denmark
• Estonia
• France
• Greece
• India
• Latvia
• Lithuania
• Malta
• The Netherlands
• New Zealand
• Norway
• Poland
• South Africa
• United Kingdom
• United States
• USSR
• Yugoslavia

and others.

(list source)