| Type: | Ortsteil |
| Town: | Lauscha |
| Image Coa: | Wappen Ernstthal.png |
| Coordinates: | 50.4894°N 11.1808°W |
| State: | Thuringia |
| District: | Sonneberg |
| Elevation: | 770 |
| Population: | 950 |
| Postal Code: | 98724 |
| Area Code: | 036702 |
| Licence: | SON |
Ernstthal am Rennsteig is a municipality section of the so-called Glass-blower Town (de: Glasbläserstadt) Lauscha in the district of Sonneberg in Thuringia, Germany, close to the Thuringian Rennsteig.
Close to the Ernstthal Station and the Rennsteig rises the river Kieselbach one of the tributaries of the Lichte river.