The Triple Entente (from French entente [ɑ̃tɑ̃t] "good will") was the name given to the alliance among France, Britain and Russia after the signing of the Anglo-Russian Entente in 1907. The alliance of the three powers, supplemented by various agreements with Portugal, Japan, the United States, Brazil, Canada, and Spain, constituted a powerful counterweight to the Triple Alliance of Germany, Austria-Hungary, and Italy. (Italy had concluded an additional secret agreement with France, effectively nullifying their alliance with Germany.)

Historians continue to debate the importance of the alliance system in igniting the First World War. At the start of World War I in 1914, all three members of the Triple Entente entered it as Allies against Germany and Austria-Hungary.

Russia had previously been a member of the League of the Three Emperors with Austria-Hungary and Germany, an alliance established in 1873 between Tsar Alexander II, Emperor Franz Joseph I and Kaiser Wilhelm I. The alliance was part of the German Chancellor Otto von Bismarck′s plan to isolate France diplomatically; he feared France had revanchist aspirations and might try to regain her 1871 losses, and to fight against radical sentiments the conservative rulers found unsettling, such as the First International.

World War I (WWI), which was predominantly called the World War or the Great War from its occurrence until 1939 (World War II), and the First World War or World War I thereafter, was a major war centred in Europe that began on 28 July 1914 and lasted until 11 November 1918. It involved all the world's great powers, which were assembled in two opposing alliances: the Allies (based on the Triple Entente of the United Kingdom, France and Russia) and the Central Powers (originally centred around the Triple Alliance of Germany, Austria-Hungary and Italy; but, as Austria–Hungary had taken the offensive against the agreement, Italy did not enter into the war). These alliances both reorganised (Italy fought for the Allies), and expanded as more nations entered the war. Ultimately more than 70 million military personnel, including 60 million Europeans, were mobilised in one of the largest wars in history. More than 9 million combatants were killed, largely because of enormous increases in lethality of weapons, thanks to new technology, without corresponding improvements in protection or mobility. It was the sixth-deadliest conflict in world history, subsequently paving the way for various political changes such as revolutions in the nations involved.