Claim: World War I involved one group of countries fighting another.

The Triple Entente -LRB- from French entente -LSB- ɑ̃tɑ̃t -RSB- `` friendship , understanding , agreement '' -RRB- was the understanding linking the Russian Empire , the French Third Republic , and the United Kingdom of Great Britain and Ireland after the signing of the Anglo-Russian Entente on 31 August 1907 . The understanding between the three powers , supplemented by agreements with Japan and Portugal , constituted a powerful counterweight to the Triple Alliance of Germany , Austria-Hungary and the Kingdom of Italy , though Italy did not side with Germany and Austria during World War I and joined the Entente Powers instead , in the 1915 Treaty of London .   Historians continue to debate the importance of the alliance system in igniting the Great War . At the start of World War I in 1914 , all three Triple Entente members entered it as Allies of World War I against the Central Powers , Germany and Austria-Hungary . However , it is important to note that the Triple Entente , in contrast to the Triple Alliance or the Franco-Russian Alliance , was not an alliance of mutual defence and Britain therefore felt free to make its own foreign policy decisions in the July crisis in 1914 .