The Ottoman Empire's entry into World War I began when two recently purchased ships of its navy, which were still crewed by German sailors and commanded by their German admiral, carried out the Black Sea Raid, a surprise attack against Russian ports, on 29 October 1914. Russia replied by declaring war on 1 November 1914. Russia's allies, Britain and France, declared war on the Ottoman Empire on 5 November 1914. The reasons for the Ottoman action were not immediately clear. The Ottoman government had declared neutrality in the recently started war, and negotiations with both sides were underway.

The Black Sea raid was an Ottoman naval sortie against Russian ports in the Black Sea on 29 October 1914, supported by Germany, that led to the Ottoman entry into World War I. The attack was conceived by Ottoman War Minister Enver Pasha, German Admiral Wilhelm Souchon, and the German foreign ministry.