Ernest Augustus or Ernst August may refer to:
Royalty House of Hanover Ernest Augustus, Elector of Hanover (1629–1698), father of King George I of Great Britain Ernest Augustus, Duke of York and Albany, Prince-Bishop of Osnabrück, son of the previous Ernest Augustus, King of Hanover (1771–1851), son of King George III of the United Kingdom Ernest Augustus, Crown Prince of Hanover, (1845–1923), son of George V of Hanover Ernest Augustus, Duke of Brunswick (1887–1953), son of the previous Prince Ernest Augustus of Hanover (born 1914) (1914–1987), son of the previous Prince Ernst August von Hannover (born 1954), son of the previous Prince Ernst August of Hanover (born 1983), son of previous
House of Wettin Ernest Augustus I, Duke of Saxe-Weimar-Eisenach (1688–1748) Ernest Augustus II, Duke of Saxe-Weimar-Eisenach (1737–1758), son of the previous
Other Ernst August (ship), a ship named after Ernest Augustus, King of Hanover