John Ernest II
| Johann Ernst II | |
|---|---|
| Duke of Saxe-Weimar | |
| Reign | 1662–1683 |
| Predecessor | William |
| Successor | William Ernest |
| Born | 11 September 1627 Weimar |
| Died | 15 May 1683 (aged 55) Weimar |
| Spouse | Christine Elisabeth of Holstein-Sonderburg |
| Issue | Anna Dorothea, Abbess of Quedlinburg Wilhelmine Christine, Countess of Schwarzburg-Sondershausen Eleonore Sophie, Duchess of Saxe-Merseburg-Lauchstädt William Ernest, Duke of Saxe-Weimar John Ernest III, Duke of Saxe-Weimar |
| House | Wettin |
| Father | William, Duke of Saxe-Weimar |
| Mother | Eleonore Dorothea of Anhalt-Dessau |
| Religion | Lutheran |
John Ernest II (11 September 1627, in Weimar – 15 May 1683, in Weimar), was a duke of Saxe-Weimar. He was the second but eldest surviving son of William, Duke of Saxe-Weimar, and Eleonore Dorothea of Anhalt-Dessau.