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World War II Status

Allied Co-Belligerent



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Allies During WWII

Roughly twenty-one years after the end of World War I, the second world war began. World War II found many of the same allies of World War I teaming up against the reformed Central Powers, which were renamed the Axis Powers in World War II. As before, Great Britain and France led the allies at the start, this time joined by Poland, a country that did not exist as an independent nation until the end of WWI. Independent nations of the British Empire, such as Canada, Australia, and South Africa, joined the Allies shortly thereafter. Over time, more than twenty Allies would join the cause as the number of countries involved in WWII continued to expand, engulfing even countries that have no military.

The Big Three Allies and the Four Powers of World War II

Three of the most powerful Allies entered the war—or at least the Allied cause—late, but had a massive impact when they did. First of these was Russia, which actually began WWII as one of the Axis Powers, having signed a non-aggression pact with Germany. In fact, Russia had assisted Germany in its initial invasion of Poland in 1939. However, Germany broke the non-aggression pact itself and attacked Russia in 1941, prompting Russia to switch its allegiance to the Allies.

As it had in the first World War, the United States spent the early portion of World War II attempting to distance itself from the affairs of Europe and join the list of countries that remained neutral in WWII. That all changed when the Japanese bombed the U.S. Naval base at Pearl Harbor, Hawaii in December 1941. In response, the United States entered the war in earnest, participating heavily in both the European and Pacific fronts.

China also joined the Allies in December 1941, an important development even though the country had already been at war with Axis power Japan since 1937. The United Kingdom, Russia, and the United States would come to be known as the "Big Three," and also (with China included) as the "Four Powers." They remain military powers today, with three of the largest militaries of any country on Earth, as well as some of the largest nuclear arsenals in the world. Once World War II ended, the Allies would establish the United Nations, an organization that today includes 193 countries and two observer states.

List of Allied Countries in World War II:

CountryDate JoinedCountryDate JoinedCountryDate Joined
Argentina27 March 1945Finland*15 Sept. 1944Oman10 Sept. 1939
Australia3 Sept. 1939France3 Sept. 1939Panama7 Dec. 1941
Belgium10 May 1940Greece28 Oct 1940Paraguay7 Feb. 1945
Bolivia7 Apr. 1943Guatemala9 Dec. 1941Peru12 Feb. 1945
Brazil22 Aug. 1942Haiti8 Dec 1941Philippines8 Dec 1941
British India3 Sept. 1939Honduras8 Dec. 1941Poland1 Sept. 1939
Bulgaria*8 Sept. 1944Iran9 Sept. 1943Romania*25 Aug. 1944
Canada10 Sept. 1939Iraq16 Jan. 1943Saudi Arabia1 Mar. 1945
Chile11 April 1945Lebanon27 Feb. 1945South Africa6 Sept. 1939
China9 Dec 1941Italy*10 Oct. 1943South Korea*10 Dec. 1941
Colombia26 July 1943Liberia27 Jan. 1944Soviet Union22 June 1941
Costa Rica8 Dec. 1941Luxembourg10 May 1940Syria26 Feb. 1945
Cuba9 Dec. 1941Mexico22 May 1942Turkey23 Feb. 1945
Czechoslovakia*16 Dec. 1941Mongolia1 Aug 1945United Kingdom3 Sept. 1939
Denmark8 Apr. 1940Nepal4 Sept. 1939United States8 Dec. 1941
Dominican Rep.8 Dec. 1941Netherlands10 May 1940Uruguay15 Feb. 1945
Ecuador2 Feb. 1945New Zealand3 Sept. 1939Venezuela15 Feb. 1945
Egypt24 Feb. 1945Nicaragua8 Dec. 1941Vietnam (Viet Minh)7 Dec. 1941
El Salvador8 Dec. 1941Norway8 Apr. 1940Yugoslavia6 Apr. 1941
Ethiopia14 Dec. 1942

* Notes:

  • Bulgaria began the war as an Axis nation.
  • Czechoslovakia's legitimate government declarted its allegiance while in exile, as the country was occupied.
  • Finland fought alongside Germany and against Russia in the Continuation War from 1941-1944 and did not declare war on Germany until 3 March 1945. However, the declaration was made retroactive to 15 September 1944.
  • Italy and Romania began the war as Axis nations.
  • South Korea's government was provisional at the time of its declaration.
  • Vietnam's allegiance was declared by the Viet Minh, a government that was revolutionary at the time.

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World War II Status
Date Joined
Additional Details
ArgentinaAllied Co-Belligerent03-27-1945
Argentina remained neutral for most of the war. Did not sign the Declaration of United Nations, but ...
At the time of WWII, modern-day Bangladesh was part of UK-controlled British India.
Bulgaria was part of the Axis powers from 1941-1944, then switched sides to the Allies in 1944.
Declared war on Japan.
At war with Japan since 1937.
Costa RicaAllies12-08-1941
Did not join Axis and supplied only volunteer troops, but was occupied by Germany through much of th...
Dominican RepublicAllies12-08-1941
El SalvadorAllies12-08-1941
Finland fought alongside Germany and against Russia in the Continuation War from 1941-1944 and did n...
At the time of WWII, modern-day India was part of UK-controlled British India.
Iran planned to remain neutral in WWII, but was occupied by both sides and eventually joined the All...
Neutral government overthrown by coup in 1941. New regime supported Axis and fought against Britain,...
Originally one of the major Axis powers, Italy left the Axis once its dictatorial ruler, Benito Muss...
Declared war on Japan.
New ZealandAllies09-03-1939
At the time of WWII, modern-day Pakistan was part of UK-controlled British India.
Originally an Axis power, Romania surrendered to Russia in 1944 and subsequently became an Allied pa...
Saudi ArabiaAllies03-01-1945
Neutral through most of the war, but supported Allies with oil, hosted an Allied air base, and decla...
South AfricaAllies09-06-1939
South KoreaAllies12-10-1941
South Korea's government was provisional at the time of its declaration.
Maintained neutrality until they entered a friendship agreement with Germany in 1941, but did not se...
United KingdomAllies09-03-1939
United StatesAllies12-08-1941
Declared war on Japan on Dec 8, 1941, the day after the Pearl Harbor attack. Germany and Italy decla...
As Vietnam was occupied and ruled by Japan starting in 1940, Vietnam's allegiance was declared by th...
showing: 57 rows

Who were the Allies in World War 2?

The main members of the Allies during World War 2 were the United Kingdom, the United States, the Soviet Union, and China. This group went on to become the United Nations after the war.

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