The abdication of Wilhelm II as German Emperor and King of Prussia was declared by Chancellor Maximilian of Baden on 9 November 1918; it was formally affirmed by a written statement of Wilhelm on 28 November, made while in exile in Amerongen, the Netherlands. The abdication caused the German Empire to dissolve and concluded the House of Hohenzollern's 500-year rule over Prussia and its predecessor state, Brandenburg. Wilhelm reigned from 15 June 1888 to 9 November 1918. As a result of the abdication and the German Revolution of 1918–19, the nobility as a legally-defined class was abolished. Following the proclamation of the Weimar Constitution on 11 August 1919, all Germans were declared equal before the law. The rulers of the twenty-two constituent states of the Empire also had to relinquish their monarchical titles and domains.

Wilhelm II was the last German Emperor and King of Prussia from 1888 until his abdication in 1918, which marked the end of the German Empire and the House of Hohenzollern's 300-year reign in Prussia and 500-year reign in Brandenburg.