Wenceslaus (German: Wenzel; sometimes known as "the Drunkard", Czech: Václav IV) of the house of Luxembourg (born February 26, 1361, died August 16 1419) succeeded his father Charles IV as Holy Roman Emperor (ruled 1378 - 1400) and as king of Bohemia (ruled 1378 - 1419).

Accusing Wenceslaus of devoting far more attention to his Bohemian than to his German duties, and of weakness in agreeing with Charles VI of France to end their support of rival Popes, the princes of the German states deposed him as Emperor in August 1400 in favour of Rupert III, Count Palatine of the Rhine: Wenceslaus refused for a decade to renounce the Imperial crown.

As King Wenceslaus IV of Bohemia until his death on 16 August 1419, he came into repeated conflict with the nobility and sought to protect the religious reformer Jan Hus and his followers against the demands of the established Church for their suppression as heretics. After Hus's execution in Constance (1415), Wenceslaus's reign ended with the first stirrings of the Hussite Wars which would follow his death.