Johann Ernst II Duke of Saxe Weimar
- Category : Notable-Famous-Royal-family
- Type : MGE
- Profile : 6/2 - Role Model / Hermit
- Definition : Single
- Incarnation Cross : LAX The Plane 2
German nobleman, a duke of Saxe-Weimar, 1662–1683. He was the second but eldest surviving son of Wilhelm, Duke of Saxe-Weimar, and Eleonore Dorothea of Anhalt-Dessau. On 14 August 1656, John Ernest married Christine Elisabeth of Holstein-Sonderburg, (1638–1679), daughter of John Christian, Duke of Schleswig-Holstein-Sonderburg (1607–1653). They had five children.
He died 15 May 1683 in Weimar.