The Ottoman Empire came into World War I as one of the Central Powers by carrying out a surprise attack on the Black Sea coast of Russia on 29 October 1914, with Russia responding by declaring war on 2 November 1914. Ottoman forces fought the Entente in the Balkans and the Middle Eastern theatre of World War I. Mehmed V, Sultan of the Ottoman Empire, declared Jihad against the powers of the Triple Entente during World War I.^[77] The declaration, which called for Muslims to support the Ottomans in Entente-controlled areas and for jihad against "all enemies of the Ottoman Empire, except the Central Powers",^[78] was initially drafted on the 11 November and first publicly read out in front of a large crowd on 14 November.^[77]

Arab tribes in Mesopotamia were initially enthusiastic about the edict. However, following British victories in the Mesopotamian campaign in 1914 and 1915, enthusiasm declined, and some chieftains like Mudbir al-Far'un adopted a more neutral, if not pro-British, stance.^[79]

There were hopes and fears that non-Turkish Muslims would side with Ottoman Turkey, but according to some historians, the appeal did not "unite the Muslim world",^[80] and Muslims did not turn on their non-Muslim commanders in the Allied forces. However, other historians point to the 1915 Singapore Mutiny and alleged that the call did have a considerable impact on Muslims around the world.^[81] In a 2017 article, it was concluded that the declaration, as well as earlier jihad propaganda, had a strong impact on attaining the loyalty of Kurdish tribes, who played a major role in the Armenian and Assyrian genocides.^[82]

The war led to the end of the caliphate as the Ottoman Empire entered on the side of the war's losers and surrendered by agreeing to "viciously punitive" conditions. On 30 October 1918, the Armistice of Mudros was signed, ending Ottoman involvement in World War 1. The Ottoman public, however, was given misleadingly positive impressions of the severity of the terms of the Armistice. They thought its terms were considerably more lenient than they actually were, a source of discontent later that the Allies had betrayed the offered terms.