The Countries Involved in World War I

More than 100 nations worldwide eventually joined the conflict

Map of Alliances in World War I
Map of Alliances in World War I.

Helmandsare, Joaopais, El Jaber, Aivazovsky 

The relevance of "world" in the term "World War I" is often difficult to see, because books, articles, and documentaries generally concentrate on Europe and America; even the Middle East and Anzac forces (Australian and New Zealand) are often glossed over. The use of "world" isn't, as non-Europeans might suspect, the result of self-important bias toward the West, because a full list of the countries involved in WWI reveals a picture of global activity. Between 1914 and 1918, more than 100 countries from Africa, the Americas, Asia, Australasia, and Europe were part of the conflict.

Key Takeaways: Countries Involved in World War I

  • Although most of the battles of World War I occurred in western Europe, many other countries were involved in the events. 
  • Some, like Canada and the U.S., declared war, sent troops, and manufactured armaments.
  • Other countries kept prisoner of war camps or sent infrastructure workers. 
  • Many countries in Africa and Asia were colonies of the large empires and were coerced to help with the war effort. 

How Involved Were Countries?

The levels of involvement differed hugely. Some countries mobilized millions of troops and fought hard for more than four years; some were used as reservoirs of goods and manpower by their colonial rulers, while others simply declared war later on and contributed only moral support. Many were drawn in by colonial links: When Britain, France, and Germany declared war, they also committed their empires, involving most of Africa, India, and Australasia, while the 1917 entry of the U.S. prompted much of central America to follow.

Consequently, the countries in the following list didn't necessarily send troops, and few saw fighting on their own soil; they either declared war or were considered involved in the conflict, such as being invaded before they could declare anything. It's important to remember, though, that the effects of WWI went beyond this global list. Even countries that remained neutral felt the economic and political effects of a conflict that shattered the established global order.


In 1914, 90 percent of the continent of Africa were colonies of the European powers, with only Liberia and Ethiopia retaining independence, and so much of Africa's participation was enforced or conscripted. All told, about 2.5 million Africans served as soldiers or laborers, and half that total was coercively recruited as carriers or other workers, used to build transportation and other infrastructure projects or perform auxiliary services.

The only regions to remain neutral in Africa were Ethiopia and the four small Spanish colonies of Rio de Oro (Spanish Sahara), Rio Muni, Ifni, and Spanish Morocco. Colonies in Africa that were involved in some manner included:

  • Algeria
  • Angola
  • Anglo-Egyptian Sudan
  • Basutoland
  • Bechuanaland
  • Belgian Congo
  • British East Africa (Kenya)
  • British Gold Coast
  • British Somaliland
  • Cameroon
  • Cabinda
  • Egypt
  • Eritrea
  • French Equatorial Africa
  • Gabon
  • Middle Congo
  • Ubangi-Schari
  • French Somaliland
  • French West Africa
  • Dahomey
  • Guinea
  • Ivory Coast
  • Mauretania
  • Senegal
  • Upper Senegal and Niger
  • The Gambia
  • German East Africa
  • Italian Somaliland
  • Liberia
  • Madagascar
  • Morocco
  • Portuguese East Africa (Mozambique)
  • Nigeria
  • Northern Rhodesia
  • Nyasaland
  • Sierra Leone
  • South Africa
  • South West Africa (Namibia)
  • Southern Rhodesia
  • Togoland
  • Tripoli
  • Tunisia
  • Uganda and Zanzibar


When they finally joined the war effort in 1917, the United States signed up 4 million men for the Allies. As a dominion of the United Kingdom, Canada sent 400,000 enlisted men, and, like the United States, manufactured armaments, aircraft, and ships.

Latin American governments seesawed between neutrality and entry into the war, and Brazil was the only independent South American country to declare war in WWI; it joined the Entente countries—Great Britain, France, and Russia—against Germany and Austria-Hungary in 1917. Other South American nations severed their relations with Germany but did not declare war: Bolivia, Ecuador, Peru, and Uruguay, all in 1917.

  • Bahamas
  • Barbados
  • Brazil
  • British Guiana
  • British Honduras
  • Canada
  • Costa Rica
  • Cuba
  • Falkland Islands
  • French Guiana
  • Grenada
  • Guatemala
  • Haiti
  • Honduras
  • Guadeloupe
  • Jamaica
  • Leeward Islands
  • Newfoundland
  • Nicaragua
  • Panama
  • St. Lucia
  • St. Vincent
  • Trinidad and Tobago
  • U.S.A
  • West Indies


Of all the Asian countries involved in World War I in some manner, India, a colony of the British Empire at the time, sent the most: 1.3 million troops and laborers went to the imperial war effort. China was officially neutral but provided about 200,000 laborers to the Allied forces to repair tanks. Japan sent 14 destroyers and a flagship cruiser to assist British ships in the Mediterranean Sea. Tiny Siam stayed neutral until mid-1917 and then sent 1,300 men as pilots, aircraft mechanics, automobile drivers and mechanics, and medical and support staff. Regions in Asia contributing to the war effort were:

  • Aden
  • Arabia
  • Bahrain
  • El Qatar
  • Kuwait
  • Trucial Oman
  • Borneo
  • Ceylon
  • China
  • India
  • Japan
  • Persia
  • Philippines
  • Russia
  • Siam
  • Singapore
  • Transcaucasia
  • Turkey

Australasia and Pacific Islands

The largest contributors to the war efforts were the large Australian Imperial Force (Australia still being a colony of England at the time), 330,000 soldiers sent to aid the Allies in the Middle East and Germany. Other contributing countries included:

  • Antipodes
  • Auckland
  • Austral Islands
  • Australia
  • Bismarck Archipelago
  • Bounty
  • Campbell
  • Caroline Islands
  • Chatham Islands
  • Christmas
  • Cook Islands
  • Ducie
  • Elice Islands
  • Fanning
  • Flint
  • Fiji Islands
  • Gilbert Islands
  • Kermadec Islands
  • Macquarie
  • Malden
  • Mariana Islands
  • Marquesas Islands
  • Marshal Islands
  • New Guinea
  • New Caledonia
  • New Hebrides
  • New Zealand
  • Norfolk
  • Palau Islands
  • Palmyra
  • Paumoto Islands
  • Pitcairn
  • Philippines
  • Phoenix Islands
  • Samoa Islands
  • Solomon Islands
  • Tokelau Islands
  • Tonga


Map of military alliances of Europe in 1914.
Map of military alliances of Europe in 1914. historicair

Most of the battles of World War I took place in Europe, and willingly or not, the people of most of the countries were somehow active in the conflict. For the Allies, 5 million British men served in the conflict, just under half of the available pool of men aged 18-51; 7.9 million French citizens were called to serve.

A total of 13 million German citizens fought in the war between 1914 and 1918. In the occupied territories, Germany and its allies also coerced civilians into labor: citizens from Italy, Albania, Montenegro, Serbia, Romania, and Russian Poland all had conscripts fighting or assisting with the Entente efforts.

  • Albania
  • Austria-Hungary
  • Belgium
  • Bulgaria
  • Czechoslovakia
  • Estonia
  • Finland
  • France
  • Great Britain
  • Germany
  • Greece
  • Italy
  • Latvia
  • Lithuania
  • Luxembourg
  • Malta
  • Montenegro
  • Poland
  • Portugal
  • Romania
  • Russia
  • San Marino
  • Serbia
  • Turkey

Atlantic Islands

  • Ascension
  • Sandwich Islands
  • South Georgia
  • St. Helena
  • Tristan da Cunha

Indian Ocean Islands

  • Andaman Islands
  • Cocos Islands
  • Mauritius
  • Nicobar Islands
  • Reunion
  • Seychelles

Additional References

  • Beaupré, Nicolas. "France." International Encylopedia of the First World War. Eds. Daniel, Ute, et al. Berlin: Freie Universität Berlin, 2014. Web.
  • Badsey, Stephen. "Great Britain." International Encylopedia of the First World War. Eds. Daniel, Ute, et al. Berlin: Freie Universität Berlin, 2017. Web.
  • Granatstein, J.L. "Canada." International Encylopedia of the First World War. Eds. Daniel, Ute, et al. Berlin: Freie Universität Berlin, 2018. Web.
  • Koller, Christian. "Colonial Military Participation in Europe (Africa)." International Encylopedia of the First World War. Eds. Daniel, Ute, et al. Berlin: Freie Universität Berlin, 2014. Web.
  • Rinke, Stefan and Karina Kriegsmann. "Latin America." International Encylopedia of the First World War. Eds. Daniel, Ute, et al. Berlin: Freie Universität Berlin, 2017. Web.
  • Strahan, Hew. "The First World War in Africa." Oxford: Oxford University Press, 2004. Print.
View Article Sources
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  6. Boissoneault, Lorraine. “The Surprisingly Important Role China Played in WWI.”, 17 Aug. 2017.

  7. Johnston, Eric. “Japan's Little-Known, but Significant, Role in World War I.” The Japan Times.

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Your Citation
Wilde, Robert. "The Countries Involved in World War I." ThoughtCo, Jul. 30, 2021, Wilde, Robert. (2021, July 30). The Countries Involved in World War I. Retrieved from Wilde, Robert. "The Countries Involved in World War I." ThoughtCo. (accessed March 27, 2023).