What were the countries involved in world war 1?

What were the countries involved in world war 1?

When the war started in 1914, the Allied Powers were France, Britain (and its global empire), Russia, Japan, Belgium, and Serbia (with Montenegro). The Central Powers were Germany and Austria-Hungary.

By 1915, Italy had joined the Allied Powers, while Bulgaria and the Ottoman Empire had joined the Central Powers.

In 1916, Romania and Portugal joined the Allies.

In 1917, the United States entered the war as an Associate Power on the side of the Allies. Greece also entered the war as an Allied nation.

Those were the major combatants. Several other countries in Latin America entered the war as Allies in 1917, such as Brazil who was also losing ships to unrestricted German submarine warfare. And since the European powers had empires in Africa and Asia, the war spread to those parts of the world as well. Although only four nations were officially part of the Central Powers, they had help from a number of groups, including nationalists in Ireland, Finland, Ukraine, Lithuania, and Azerbaijan (Germany was good at siding with people under the control of its enemies).