World War I was fought between two main coalitions: the Allies (Entente Powers) and the Central Powers.

Core answer

  • The war was primarily Allies vs Central Powers from 1914 to 1918.
  • It involved most major powers of Europe, plus countries from other regions like the United States and Japan.

Who were the Allies?

The Allies (also called the Entente) formed one side of World War I. Key members included:

  • France, the United Kingdom, and Russia as the original core.
  • Later joined by Italy, Japan, and the United States (from 1917).
  • Many other countries, such as Serbia, Belgium, Romania, Greece, Portugal, and British Empire dominions like Canada and Australia, also fought with the Allies.

Who were the Central Powers?

The Central Powers were the opposing coalition.

  • Main members: Germany and Austria‑Hungary at the core.
  • Later joined by the Ottoman Empire (Turkey and its Middle Eastern territories) and Bulgaria.

Simple table of the sides

[7][1][2][3][5] [2][3][5][7]
Side Main countries
Allies (Entente) France, United Kingdom, Russia, later Italy, Japan, United States, plus others like Serbia and Belgium.
Central Powers Germany, Austria‑Hungary, Ottoman Empire, Bulgaria.

One‑sentence recap

World War I was between the Allies (France, Britain, Russia, later the US and others) and the Central Powers (Germany, Austria‑Hungary, the Ottoman Empire, Bulgaria).

Information gathered from public forums or data available on the internet and portrayed here.