Wilhelm II (Friedrich Wilhelm Viktor Albert; 27 January 1859 – 4 June 1941) was the last German Emperor (German: Kaiser) and King of Prussia, reigning from 15 June 1888 until his abdication on 9 November 1918. Despite strengthening the German Empire's position as a great power by building a powerful navy, his tactless public statements and erratic foreign policy greatly antagonized the international community and are considered by many to be one of the underlying causes of World War I. When the German war effort collapsed after a series of crushing defeats on the Western Front in 1918, he was forced to abdicate, thereby marking the end of the German Empire and the House of Hohenzollern's 300-year reign in Prussia and 500-year reign in Brandenburg.

Born during the reign of his great-uncle Frederick William IV of Prussia, Wilhelm was the son of Prince Frederick William and Victoria, Princess Royal. Through his mother, he was the eldest grandchild of Queen Victoria of the United Kingdom. In March 1888, Wilhelm's father ascended the German and Prussian thrones as Frederick III. Frederick died just 99 days later, and his son succeeded him as Wilhelm II.