Ernest Augustus (German: Ernst August; Latin: Ernestus Augustus; 20 November 1629 – 23 January 1698) is duke of Brunswick-Lüneburg and rules over the Principality of Calenberg (with its capital Hanover) subdivision of the duchy.

He is appointed prince-elector, but dies before the appointment becomes effective.

He is also Administrator of the Prince-Bishopric of Osnabrück.

Lady Diana, Princess of Wales is his descendant.