Participants in World War I



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

The Entente Forces
Note: The Entente Forces are sometimes also referred to as the Entente Powers or Allies of World War I.


 * 🇦🇱 Albania
 * 🇦🇩 Andorra
 * 🇧🇪 Belgium
 * 🇧🇴 Bolivia
 * 🇧🇷 Brazil
 * Republic of China
 * 🇨🇷 Costa Rica
 * 🇨🇺 Cuba
 * Czechoslovak Legions
 * 🇪🇨 Ecuador
 * 🇫🇷 France
 * 🇬🇷 Greece
 * 🇬🇹 Guatemala
 * 🇭🇹 Haiti
 * 🇭🇳 Honduras
 * 🇮🇹 Italy
 * Empire of Japan
 * 🇱🇷 Liberia
 * 🇲🇪 Montenegro
 * 🇳🇮 Nicaragua
 * 🇵🇦 Panama
 * 🇵🇪 Peru
 * 🇵🇹 Portugal
 * 🇷🇴 Romania
 * Russian Empire
 * 🇸🇲 San Marino
 * Kingdom of Serbia
 * 🇹🇭 Siam (now Thailand)
 * 🇬🇧 United Kingdom
 * 🇦🇺 Australia
 * 🇨🇦 Canada
 * 🇮🇳 India (Now India, Bangladesh, Burma and Pakistan)
 * Newfoundland
 * 🇳🇿 New Zealand
 * 🇿🇦 South Africa
 * 🇬🇧 British crown colonies
 * 🇺🇸 United States
 * Alaska
 * Hawaii
 * 🇺🇸 Philippines
 * 🇵🇷 Puerto Rico
 * 🇺🇸 Other unincorporated territories
 * 🇺🇾 Uruguay

The Central Powers

 * Austria-Hungary
 * 🇧🇬 Bulgaria
 * German Empire
 * Ottoman Empire

Neutral states

 * 🇦🇫 Afghanistan - Did not support or oppose any nation.
 * 🇦🇷 Argentina
 * 🇨🇱 Chile
 * 🇨🇴 Colombia
 * 🇩🇰 Denmark - Traded with both sides.
 * 🇸🇻 El Salvador
 * 🇪🇹 Ethiopia
 * 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.
 * 🇲🇽 🇲🇽 Mexico - Declined an alliance with Germany (see Zimmermann Telegram). An ally to the United States by treaty (see ABC countries).
 * 🇳🇱 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 British and Russian troops.
 * 🇪🇸 Spain - Also treaty bound ally to the United Kingdom.
 * 🇸🇪 Sweden - Financially supported Germany.
 * 🇨🇭 Switzerland - Switzerland did declare a "state of siege".
 * Tibet
 * 🇻🇪 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.