The countries that were involved in the war are as follows by type:
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Axis Powers (signers of the Tripartite Treaty)
Co-signers of the Tripartite Treaty
Countries that were annexed by, or at war with, Axis Powers before the World
War II
Allied Powers
Supporters of the Allies
Countries that were attacked, occupied, or switched sides during the war
(Most countries below had declared their neutrality before being
assaulted.)
Countries that remained nominally neutral
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Axis Powers (signers of the Tripartite Treaty)
- Germany
- Italy
- Japan
Co-signers of the Tripartite Treaty
- Bulgaria (March 1st, 1941)
- Hungary (November 20th, 1940)
- Romania (November 23rd, 1940)
- Slovakia(1) (November 24th, 1940)
Countries that were annexed by, or at war with, Axis Powers before the World
War II
- Austria (annexed to Germany, "Anschluss", March 13th,
1938) - Ethiopia (annexed by Italy in 1936, after the Abyssinia
crisis, independence restored in 1941) - Republic of China (at war with Japan since 1931)
Allied Powers
- Australia
- Brazil
- Canada
- Newfoundland
- New Zealand
- South Africa
- Soviet Union (from June 1941)
- United Kingdom
- United States (from December 1941)
Supporters of the Allies
- Argentina
- Bolivia
- Chile
- Colombia
- Costa Rica
- Cuba
- Dominican Republic
- Ecuador
- Egypt(2)
- El Salvador
- Guatemala
- Haiti
- Honduras
- Iraq
- Lebanon
- Liberia
- Mexico
- Mongolia
- Nicaragua
- Panama
- Paraguay
- Peru
- Saudi Arabia
- Turkey
- Uruguay
- Venezuela
Countries that were attacked, occupied, or switched sides during the war
(Most countries below had declared their neutrality before being
assaulted.)
- Algeria
- Albania (occupied by Italy April 7th 1939, by Germany
September 26th 1943) - Belgium (invaded by Germany May 10th 1940)
- Burma
- Czechoslovakia(1) (Bohemia and Moravia occupied by Germany
March 15th 1939) - Denmark (occupied by Germany April 9th 1940, Greenland
occupied by USA April 9th 1941) - Estonia (occupied by the Soviet Union from June 18th 1940,
by Germany September 5th 1941, re-annexed by the Soviet Union in 1944) - Finland (attacked by the Soviet Union November 30th 1939
and June 26th 1941) - France (surrendered to Germany June 22nd 1940)
- Greece (invaded by Italy October 28th 1940, German
occupation from April 6th 1941) - Iceland (occupied by Great Britain May 10th 1940, by USA
from July 1941) - India
- Iran
- Latvia (occupied by the Soviet Union from June 18th 1940,
by Germany June 25th 1941, re-annexed by the Soviet Union in 1944) - Lithuania (occupied by the Soviet Union from June 18th
1940, by Germany June 22nd 1941, re-annexed by the Soviet Union in 1944) - Luxembourg (invaded by Germany May 10th 1940)
- Morocco
- The Netherlands (invaded by Germany May 10th 1940)
- New Guinea
- Norway (invaded by Germany April 9th 1940)
- Philippines
- Poland (invaded by Germany and the Soviet Union in
September 1939) - Singapore
- Syria
- Thailand
- Tunisia (Occupied by USA in 1943)
- Yugoslavia(3) (German occupation from April 6th 1941)
Countries that remained nominally neutral
- Ireland
- Portugal
- Spain
- Sweden (with exception for the Winter War)
- Switzerland