The Ottoman Empire's entry into World War I marked a pivotal moment in the conflict, affecting not only regional but global geopolitical dynamics. In October 1914, the Ottoman government made a decisive move by declaring war on Russia after having initially maintained a position of neutrality. A significant factor motivating this decision was the maritime engagement between the Ottoman Navy, supported by German technology and advisors, and Russian naval forces. Subsequently, an Ottoman fleet, hoping to assert its dominance in the Black Sea, engaged in attacks against enemy shipping. This aggressive naval action catalyzed the formal declaration of war against Russia on October 29, 1914.

The Ottomans aligned themselves with the Central Powers, comprising Germany and Austria-Hungary. This strategic alliance was primarily motivated by a desire to reclaim lost territories and reshape the balance of power in favor of the Ottomans. The entry of the Ottomans into World War I significantly expanded the war's theater, drawing in military engagements across the Balkans, the Caucasus, and eventually the Middle East. The Ottoman Empire's involvement was characterized by a series of campaigns against Allied forces, including the Gallipoli Campaign, where the Ottomans successfully defended against the British and Commonwealth invasion, marking a critical moment in the war.

The war also had profound implications for the Ottoman Empire itself, hastening its decline and leading to significant political, social, and territorial changes. As the empire fought on multiple fronts, internal dissent grew, exacerbating ethnic tensions and leading to catastrophic events such as the Armenian Genocide. By the end of World War I, the empire would be dismantled, leading directly to the establishment of modern Turkey and the redrawing of national boundaries in the Middle East, effects that still resonate in contemporary geopolitics.