Ernest I or Ernst I can refer to:
- Ernest I, Duke of Swabia (reigned 1012–15)
- Ernest I, Prince of Anhalt-Dessau (died 1516)
- Ernest I, Duke of Brunswick-Lüneburg (1497–1546), Ernest the Confessor
- Ernst I, Duke of Saxe-Coburg-Altenburg (1601–1675), Ernest the Pious
- Ernst I, Duke of Saxe-Coburg and Gotha (1784–1844), father of Prince Albert, the consort of Queen Victoria
- Ernst I, Prince of Hohenlohe-Langenburg (1794–1860)
- Ernest Augustus I, Duke of Saxe-Weimar-Eisenach (1688–1748)
- Ernest Frederick I, Duke of Saxe-Hildburghausen (1681–1724)
- Ernest Günther I, Duke of Schleswig-Holstein-Sonderburg-Augustenburg (1609–1689)
- Ernst Ludwig I, Duke of Saxe-Meiningen (1672–1724)
This disambiguation page lists articles about people with the same name.
If an internal link led you here, you may wish to change the link to point directly to the intended article.
If an internal link led you here, you may wish to change the link to point directly to the intended article.