The following is a list of the major belligerents of World War I:
Allied Power[]
- Triple Entente
|
Central Power[]
- Triple Alliance
|
- Co-belligerents
|
- Co-belligerents
- Tsardom of Bulgaria (1915–18)
- Emirate of Jabal Shammar
- Senussi Order
- Sultanate of Darfur
- Imamate of Oman
|
- Emirate of Nejd and Hasa
- Most Serene Republic of San Marino (Jun. 1915)
- Hashemite Kingdom of Hejaz (1916–18)
- Portuguese Republic (Mar. 1916)
- Kingdom of Romania (Aug. 1916 - May. 1918)
- Republic of Panama (Dec. 1917)
- Peruvian Republic (Oct. 1917)
- Oriental Republic of Uruguay (Oct. 1917)
- United States of America (1917–18)
- Kingdom of Greece (Jun. 1917)
- Kingdom of Siam (Thailand-Siam) (1917–18)
- Principality of Albania
- First Czechoslovak Republic (Oct. 1918)
- Kingdom of Nepal
- Republic of Cuba (Apr. 1917)
- Republic of Bolivia (Apr. 1917)
- Republic of China (Aug. 1917)
- Republic of Liberia (Aug. 1917)
- Republic of the United States of Brazil (Oct. 1917)
- Kingdom of Finland (later Republic) (Oct. 1917)
- Republic of Ecuador (Dec. 1917)
- Principality of Andorra
- Republic of Guatemala (Apr. 1918)
- Republic of Nicaragua (May. 1918)
- First Republic of Armenia (May. 1918)
- Republic of Costa Rica (May. 1918)
- Republic of Haiti (Jul. 1918)
- Republic of Honduras (Jul. 1918)
|
