European military alliances prior to World War I. Beige indicates countries with no alliance at that time; Photo Credit – Wikipedia
The Entente Powers (also known as the Allies of World War I or the Allies)
*monarchy
- Andorra
- Armenia
- Belgium*
- Brazil
- Republic of China
- Costa Rica
- Cuba
- Czechoslovak Legions (volunteer armed forces composed predominantly of Czechs and Slovaks)
- France (and the French colonial empire)
- Greece*
- Guatemala
- Haiti
- Honduras
- Italy* – Italy had been part of the Central Powers, but joined the Allies in 1915
- Japan* (Korea, Taiwan)
- Liberia
- Montenegro*
- Nepal*
- New Hebrides (British-French co-Dominion, now Vanuatu)
- Nicaragua
- Panama
- Portugal (and the Portuguese colonial empire)
- Romania*
- Russia*
- Serbia*
- Siam* (now Thailand)
- United Kingdom* [and the British Empire including Canada, British India (now India, Bangladesh, Burma and Pakistan), Newfoundland, Australia, New Zealand, Malta, South Africa, Rhodesia (now Zimbabwe and Zambia), British Crown Colonies]
- United States (including Alaska, Hawaii, Philippines, Puerto Rico)
The Central Powers
- Austria-Hungary* (Today the land occupied by Austria-Hungary includes parts of these current countries: Austria, Bosnia and Herzegovina, Croatia, Czech Republic, Hungary, Italy, Montenegro, Poland, Romania, Serbia, Slovakia, Slovenia, and Ukraine)
- Azerbaijan Democratic Republic
- Bulgaria*
- Dervish State* (now parts of Ethiopia and Somalia)
- Germany* (and German colonial empire)
- Jabal Shammar* (now parts of Saudi Arabia, Iraq, and Jordan)
- Ottoman Empire* (Today the land occupied by the Ottoman Empire includes parts of these current countries: Albania, Algeria, Armenia, Austria, Azerbaijan, Bahrain, Bosnia and Herzegovina, Bulgaria, Croatia, Cyprus, Egypt, Eritrea, Georgia, Greece, Hungary, Iran, Iraq, Israel, Jordan, Kuwait, Lebanon, Libya, Macedonia, Moldova, Montenegro, Oman, State of Palestine, Qatar, Romania, Russia, Saudi Arabia, Serbia, Slovakia, Somalia, Sudan, Syria, Tunisia, Turkey, United Arab Emirates, Ukraine, and Yemen)
Neutral countries
- Afghanistan* – Received a German diplomatic mission trying to convince it to act against the British in India
- Albania* – In political chaos since the beginning of the war, the country was occupied by both Central and Allied powers but never declared war on either side
- Argentina
- Bolivia
- Bhutan*
- Chile
- Colombia
- Denmark*
- El Salvador
- Ethiopia* – 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* (now part of China)
- Mexico – Declined an alliance with Germany (see Zimmermann Telegram)
- Monaco*
- Netherlands* – Ally of the United Kingdom by treaty; Traded with both sides
- Norway* – Gave naval assistance to the United Kingdom
- Paraguay
- Persia* (later Iran) – Civil dispute and Allied Campaign against Ottomans
- Spain* – Ally of the United Kingdom by treaty
- Spitsbergen – Danish-Norwegian co-Dominion (now part of Norway)
- Sweden* – Non-belligerent
- Switzerland – Declared a “state of siege”
- Tibet – Unrecognized but independent of China from 1912
- Venezuela – Supplied the Allies with oil