| Kœstlach | |
| Native Name: | Cheschli |
| Commune Status: | Commune |
| Image Coat Of Arms: | Blason de la ville de Koestlach (68).svg |
| Arrondissement: | Altkirch |
| Canton: | Altkirch |
| Insee: | 68169 |
| Postal Code: | 68480 |
| Mayor: | André Lehmes[1] |
| Term: | 2020 - 2026 |
| Coordinates: | 47.5069°N 7.2719°W |
| Elevation M: | 468 |
| Elevation Min M: | 423 |
| Elevation Max M: | 650 |
| Area Km2: | 8.23 |
Kœstlach (in French pronounced as /kœstlax/; Swiss German; Alemannic; Alsatian: Cheschli; German: Köstlach) is a commune in the Haut-Rhin department in Alsace in north-eastern France.