| Christian Ernest II | |
| Succession: | Duke of Saxe-Coburg-Saalfeld |
| Reign: | 17 February 1729 – 4 September 1745 |
| Predecessor: | John Ernest |
| Successor: | Francis Josias |
| Spouse: | Christiane Fredericka of Koss |
| House: | Wettin |
| Father: | John Ernest IV, Duke of Saxe-Coburg-Saalfeld |
| Mother: | Sophie Hedwig of Saxe-Merseburg |
| Birth Date: | 18 August 1683 |
| Birth Place: | Saalfeld |
| Death Place: | Saalfeld |
| Religion: | Lutheranism |
Christian Ernst II, Duke of Saxe-Coburg-Saalfeld (Saalfeld, 18 August 1683 - Saalfeld, 4 September 1745), was a duke of Saxe-Coburg-Saalfeld.
He was the oldest surviving son of Johann Ernst, Duke of Saxe-Coburg-Saalfeld and his first wife, Sophie Hedwig of Saxe-Merseburg.
In Naitschau on 18 August 1724, Christian Ernst married unequally with Christiane Fredericka of Koss; for this, his younger half-brother Franz Josias reclaimed the full succession of the duchy. His father, the duke Johann Ernst, determined the common government of the brothers with indivisibility of the duchy upon his death, in 1729. Christian Ernst made his residence in Saalfeld and Franz Josias moved into the Veste Coburg.
The double government soon proved impossible, and this forced the settlement of the "Coburg Eisenberg Roemhilder of Hereditary Controversy", whereby Christian Ernst received Coburg, Rodach, Mönchröden and half Neuhaus. Christian Ernst died childless and all his inheritance was taken by his half-brother, Franz Josias.