There are already a remarkable number of nations at war, yet all of today’s conflicts would still dwarf World War II. WW2 was the largest conflict in human history, involving more than 100 million people from dozens of countries (more than in WWI) dispersed worldwide.
It was the worst war ever fought, with an estimated 21-25 million military fatalities and 50-55 million civilian deaths (including the almost 6 million Jews executed in Nazi concentration camps). Many nations sought to stay neutral in the lead-up to the conflict. As the battle continued, more nations were obliged to join the Allies or the Axis Powers.
As battles were fought and lost, regions were conquered and freed, and political agreements were established and abandoned, these alliances shifted and mutated during the conflict.
One country originally supported neither side but later switched sides, while many others began as neutrals but were ultimately pushed into the fight (often after a forceful change in government). Many nations found themselves on the fence between becoming allies and Axis or even neutral.
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Who were the war allies of which countries?
France, Poland, and the United Kingdom were the Allies when World War II started in 1939. Days later, the British dominions of Australia, Canada, New Zealand, and South Africa merged into a single nation.
As the war progressed, more nations joined the Allies, including two large powers that had originally planned to stay neutral.
A non-aggression agreement between Russia and Germany had led to Russia’s participation in the German invasion of Poland. As a result of Germany’s invasion of Russia in Operation Barbarossa in June 1941, the Soviet Union rapidly allied itself with the Allies.
The assault on Pearl Harbor by Axis power Japan in December 1941 caused the United States, the second previously neutral nation, to enter the war. Since 1937, China had been engaged in a war with Japan, and in December 1941, it joined the Allies.
The Four Powers, which included the Big Three—the United Kingdom, the United States, and Russia—and China- were in charge of the Allied nations. There were also contributions from over twenty more nations.
Declaration of United Nations made by the Four Powers and 22 more nations on January 1 and 2, 1942, formally established the Allies’ unity. When the United Nations was officially established in 1945, the proclamation became the Charter of the Organization.
Allied countries in World War II:
|Country||Date Joined||Country||Date Joined||Country||Date Joined|
|Argentina||27 March 1945||Finland*||15 Sept. 1944||Oman||10 Sept. 1939|
|Australia||3 Sept. 1939||France||3 Sept. 1939||Panama||7 Dec. 1941|
|Belgium||10 May 1940||Belgium||28 Oct 1940||Paraguay||7 Feb. 1945|
|Bolivia||7 Apr. 1943||Guatemala||9 Dec. 1941||Peru||12 Feb. 1945|
|Brazil||22 Aug. 1942||Haiti||8 Dec 1941||Philippines||8 Dec 1941|
|British India||3 Sept. 1939||Honduras||8 Dec. 1941||Poland||1 Sept. 1939|
|Bulgaria*||8 Sept. 1944||Iran||9 Sept. 1943||Romania*||25 Aug. 1944|
|Canada||10 Sept. 1939||Iraq||16 Jan. 1943||Saudi Arabia||1 Mar. 1945|
|Chile||11 April 1945||Lebanon||27 Feb. 1945||South Africa||6 Sept. 1939|
|China||9 Dec 1941||Italy*||10 Oct. 1943||South Korea*||10 Dec. 1941|
|Colombia||26 July 1943||Liberia||27 Jan. 1944||Soviet Union||22 June 1941|
|Costa Rica||8 Dec. 1941||Luxembourg||10 May 1940||Syria||26 Feb. 1945|
|Cuba||9 Dec. 1941||Mexico||22 May 1942||Turkey||23 Feb. 1945|
|Czechoslovakia*||16 Dec. 1941||Mongolia||1 Aug 1945||United Kingdom||3 Sept. 1939|
|Denmark||8 Apr. 1940||Nepal||4 Sept. 1939||United States||8 Dec. 1941|
|Dominican Rep.||8 Dec. 1941||Netherlands||10 May 1940||Uruguay||15 Feb. 1945|
|Ecuador||2 Feb. 1945||New Zealand||3 Sept. 1939||Venezuela||15 Feb. 1945|
|Egypt||24 Feb. 1945||Nicaragua||8 Dec. 1941||Vietnam (Viet Minh)||7 Dec. 1941|
|El Salvador||8 Dec. 1941||Norway||8 Apr. 1940||Yugoslavia||6 Apr. 1941|
|Ethiopia||14 Dec. 1942|
- Bulgaria was a member of the Axis powers during World War II.
- At the time of the statement, the government of Czechoslovakia was in exile.
- On March 3, 1945, Finland declared war on Germany but retroactively applied the declaration to September 15, 1944, when Finland fought with Germany and Russia in the Second World War.
- Both Italy and Romania were formerly members of the Axis powers.
- The government of South Korea was just temporary.
- The Viet Minh was responsible for Vietnam’s loyalty.
During World War II, which nations were allies of the Nazis?
The Tripartite Pact of 1940 brought together Germany, Italy, and Japan, the three principal Axis countries during World War II. After then, the Tripartite Pact gained six more members.
It was easy to predict the dates of the first four: November 20, 1940, for Hungary, November 23, 1940, for Romania, and then November 24, 1940, for Slovakia, and November 25, 1940, for Bulgaria.
The Tripartite Pact’s last two members have conditions attached to them. After the deal’s signing on March 25, 1941, the government of Yugoslavia was quickly destroyed by an uprising, and the new administration repudiated the accord only two days later.
It was this deed that sparked the Germans to invade Yugoslavia. At long last, despite its status as an illegal entity with no legal standing, the German-Italian puppet state Croatia signed on April 10, 1941.
Additional to the Tripartite Pact, other nations joined the Anti-Comintern Pact, which was less stringent. In many Anti-Comintern nations, neutrality was permitted, or only voluntary participation in the Nazi army was necessary.
Others’ bilateral agreements to obey them (along with certain illegitimate governments and nazi-installed puppet nations) were even less binding.
There were also puppet states, in which a newly conquered nation’s current government would be replaced by another one that ran independently but received instructions from the puppetmaster country. This was especially common among the Axis powers, notably Japan.
Countries that supported the Nazis during World War II:
|Burma (Ba Maw govt)*||bilateral pact||Manchuko*||puppet state|
|Cambodia (Kampuchea)*||puppet state||Mongolia (Mengjiang)*||puppet state|
|Croatia||Axis||Philippines (Second Republic)*||puppet state|
|Germany||Axis||Soviet Union*||bilateral pact|
|Greece (Hellenic States)||puppet state||Spain||Anti-Comintern|
|India (Azad Hind)*||puppet state||Vichy France*||puppet state|
|Iraq||bilateral pact||Vietnam (Empire of Vietnam)*||puppet state|
- It is possible that Denmark would have stayed neutral if Germany had not occupied it during much of World War II due to the small size of its participation.
- Finnish troops fought with German troops against Russia during the Second World War but did not technically join the Axis.
- Germany occupied Poland before the Soviet Union joined the Allies.
- After a government coup, Yugoslavia agreed to join the Axis, but the pact was voided two days later.
- The governments of all other Axis nations indicated with an asterisk (*) were either puppet regimes or illegitimate.
During World War II, which nations stayed neutral?
Many nations were able to maintain their neutrality throughout World War II, despite the difficulty of the undertaking. While several nations claimed to be neutral, they still provided limited assistance to one or both sides, such as sending volunteer soldiers or permitting travel over their country’s boundaries.
World War II’s Neutral Countries:
|Iran||San Marino||Vatican City|
How long was World War II?
The German invasion of Poland on September 1, 1939, sparked a declaration of war by the governments of France and Great Britain two days later. Conflicts between Japan and numerous other Asian nations erupted as this one grew in scope.
When the Second Sino-Japanese War started on July 7, 1937, some historians believe that World War II began as early as September 19, 1931, when Japan invaded Manchuria.
Also See: Countries Involved in World War 1 2022
It’s also questionable when the battle will be over. This was known as V-J (Victory over Japan) day and marked the conclusion of World War II. However, from a legal standpoint, the war didn’t officially end until Japan’s formal surrender on September 2, 1945.
|Argentina||Allied Co-Belligerent||Stayed neutral for most of the war. Did not sign the Declaration of United Nations, but did declare war on Germany.|
|Bulgaria||both||Bulgaria was part of the Axis powers from 1941-1944, then switched sides to the Allies in 1944.|
|Burma (Ba Maw government)||Axis - Bilateral Pact||Not a legitimate government.|
|Cambodia (Kampuchea)||Axis - Puppet State||Japanese puppet state which existed for roughy five months in mid-1945|
|Chile||Allies||Declared war on Japan|
|China||Allies||At war with Japan since 1937|
|Croatia||Axis - Puppet State|
|Czechoslovakia (govt. in exile)||Allies||Government in Exile|
|Denmark||both||Did not join Axis and supplied only volunteer troops, but was occupied by Germany through much of the war.|
|Finland||both||Finland fought alongside Russia and against Russia in the Continuation War, 1941-1944, but did not join the Axis. Finland did not officially declare war on Germany until 3 March 1945, but made the declaration retroactive.|
|Germany||Axis - Major Power|
|Greece (Hellenic States)||Axis - Puppet State||Ruled by Germany/Italy. Existed May 1941 to fall 1944.|
|Hungary||Axis - Minor Power|
|India (Azad Hind)||Axis - Puppet State||Insurgent military movement allied with Axis|
|Iran||Allies||Planned to remain neutral, but was occupied by both sides and eventually joined Allies.|
|Iraq||both||Neutral government overthrown by coup in 1941. New regime supported Axis and fought against Britain, but was overthrown by Britain. Original government restored and supported the Allies|
|Italy||both||Originally one of the major Axis powers, Italy left the Axis once its dictatorial ruler, Benito Mussolini, was removed. Although Italy did not join the Allies, it did declare war on Germany, making it a co-belligerent which fought alongside the Allies.|
|Japan||Axis - Major Power|
|Laos||Axis - Puppet State||Ruled by Japan|
|Manchukuo||Axis - Puppet State||Japanese puppet state in China. Ceased to exist after Russian invasion in 1945.|
|Mongolia||Allies||Declared war on Japan|
|Mongolia (Mengjiang)||Axis - Puppet State||Ruled by Japan|
|Philippines (Second Republic)||Axis - Puppet State||Ruled by Japan|
|Romania||Allies||Originally an Axis power, Romania surrendered to Russia in 1944 and subsequently became an Allied participant.|
|Saudi Arabia||Allies||Neutral through most of the war, but supported Allies with oil, hosted an Allied air base, and declared war on Germany and Japan in 1945.|
|Slovakia||Axis - Minor Power|
|South Korea (provisional govt.)||Allies|
|Soviet Union||both||Helped Germany invade Poland before eventually joining the Allies.|
|Spain||neutral||Officially neutral, but sent volunteer soldiers to fight for Germany against Russia (and only Russia)|
|Thailand||Axis - Bilateral Pact|
|Turkey||both||Entered a friendship agreement with Germany in 1941, but did not send troops and declared war on Germany in 1945.|
|United States||Allies||Declared war on Japan on Dec 8, 1941, war on U.S. declared by Germany and Italy Dec 11, 1941|
|Vichy France||Axis - Puppet State||Illegitimate puppet government|
|Vietnam (Empire of Vietnam)||Axis - Puppet State||Ruled by Japan|
|Vietnam (Viet Minh)||Allies|
|Yugoslavia||Allies||Joined Axis out of fear of invasion, but two days later a government coup prevented ratification of the agreement.|