Participants in World War I



This is a list of countries that participated in World War I, sorted by alphabetical order.

The Entente Powers
Note: The "Entente Powers" are also known as the Allies of World War I or the Allies.
 * 🇦🇩 Andorra
 * 🇧🇪 Belgium (Belgian colonial empire)
 * 🇧🇷 Brazil
 * Republic of China
 * 🇨🇷 Costa Rica
 * 🇨🇺 Cuba
 * Czechoslovak Legions
 * 🇫🇷 France (French colonial empire)
 * undefined
 * 🇬🇹 Guatemala
 * 🇭🇹 Haiti
 * 🇭🇳 Honduras
 * undefined
 * 🇯🇵 Japan
 * 🇱🇷 Liberia
 * undefined
 * 🇳🇵 Nepal
 * 🇳🇮 Nicaragua
 * 🇵🇦 Panama
 * 🇵🇹 Portugal (Portuguese colonial empire)
 * undefined
 * undefined
 * Russian SFSR until Treaty of Brest-Litovsk
 * 🇸🇲 San Marino
 * undefined
 * 🇹🇭 Siam (now Thailand)
 * undefined (British Empire)
 * 🇨🇦 Canada
 * British India (now India, Bangladesh, Burma and Pakistan)
 * Newfoundland
 * 🇦🇺 Australia
 * 🇳🇿 New Zealand
 * [[image:Flag of Malta (1923-1943).svg|23px]] Malta
 * undefined
 * Flag of BSAC edit.svg Rhodesia (now Zimbabwe and Zambia), administered by the British South Africa Company
 * British crown colonies
 * 🇺🇸 United States
 * Alaska
 * Hawaii
 * 🇺🇸 Philippines
 * 🇵🇷 Puerto Rico
 * 🇺🇸 Other unincorporated territories

The Central Powers

 * Austria-Hungary (now Austria, Bosnia and Herzegovina, Croatia, Czech Republic, Hungary, parts of northeast Italy, northern Serbia, partially Poland, Romania, Slovakia, Slovenia and Ukraine)
 * 🇦🇿 Azerbaijan (now Azerbaijan and Eastern Armenia)
 * undefined (now Bulgaria, partially Greece, partially Republic of Macedonia)
 * Dervish flag.svg Dervish State (now parts of Somalia)
 * undefined (German colonial empire, at the time the empire occupied Burundi, Cameroon, small parts of China, partially Gabon, Germany, Ghana, Marshall Islands, Federated States of Micronesia, Namibia, northeastern Nigeria, Palau, northern Papua New Guinea, partially Poland, Republic of the Congo, Rwanda, Samoa, mainland Tanzania, and Togo)
 * Flag of the Emirate of Ha'il.svg Jabal Shammar (now most of Saudi Arabia, parts of Iraq and Jordan)
 * Ottoman Empire (now Iraq, Israel, Jordan, Lebanon, partially Saudi Arabia, Syria, most of Turkey, and other territories it lost before the war.)

Neutral countries

 * 🇦🇫 Afghanistan - received a German diplomatic mission trying to convince it to act against the British in India
 * 🇦🇷 Argentina
 * 🇧🇴 Bolivia
 * 🇧🇹 Bhutan
 * 🇨🇱 Chile
 * 🇨🇴 Colombia
 * 🇩🇰 Denmark - Denmark was terrorized by Germany leading to their entry on the Allied side near the end of the war.
 * 🇸🇻 El Salvador
 * undefined - received a German diplomatic mission trying to convince it to act against Italy, United Kingdom and France in East Africa
 * 🇱🇮 Liechtenstein - Had a customs and monetary union with Austria-Hungary.
 * 🇱🇺 Luxembourg - Never declared war on the Central Powers despite being invaded and occupied by Germany.
 * Bogd Khaanate of Mongolia -
 * 🇲🇽/🇲🇽 Mexico - Declined an alliance with Germany (see Zimmermann Telegram).
 * 🇳🇱 Netherlands - An ally of the United Kingdom by treaty. Traded with both sides.
 * 🇳🇴 Norway - Gave naval assistance to the United Kingdom.
 * 🇵🇾 Paraguay
 * Persia - Occupied by Turkish, British and Russian troops.
 * 🇪🇸 Spain - Also treaty-bound ally to the United Kingdom.
 * 🇸🇪 Sweden - Non-belligerent.
 * 🇨🇭 Switzerland - Switzerland did declare a "state of siege".
 * 🇻🇪 Venezuela - Supplied the Allies with oil.

Declarations of War
The following table shows the timeline of the several declarations of war among the belligerent powers. Entries on a yellow background show severed diplomatic relations only, not actual declarations of war.