Which countries fought for the Allies during World War I?

The Allied powers in World War I were a coalition of nations that opposed the Central Powers—primarily Germany, Austria-Hungary, and the Ottoman Empire.12

The original members of greatest import were the British Empire, France, and the Russian Empire, which formalized their alliance on September 5, 1914. Over the course of the conflict, many other nations joined the Allied cause, including Italy, which entered the war in 1915.123

The United States joined the effort in 1917; however, it technically fought as an "Associated power" to maintain a degree of political independence from the other Allies. Russia withdrew from the alliance following the 1917 revolution and its subsequent peace treaty with the Central Powers.12

By the time the Treaty of Versailles was signed in 1919, a total of 27 "Allied and Associated Powers" were recognized, including:

• Belgium, Bolivia, Brazil, China, Cuba, Czechoslovakia, Ecuador, Greece, Guatemala, Haiti, the Hejaz, Honduras, Japan, Liberia, Nicaragua, Panama, Peru, Poland, Portugal, Romania, the Serb-Croat-Slovene State, Siam, and Uruguay.12