| Lachy | |
| Commune Status: | Commune |
| Image Coat Of Arms: | Blason ville fr Lachy 51.svg |
| Arrondissement: | Épernay |
| Canton: | Sézanne-Brie et Champagne |
| Insee: | 51313 |
| Postal Code: | 51120 |
| Mayor: | Christophe Zbinden[1] |
| Term: | 2020 - 2026 |
| Coordinates: | 48.7694°N 3.7078°W |
| Elevation M: | 190 |
| Area Km2: | 16.89 |
Lachy (in French pronounced as /laʃi/) is a commune in the Marne department in north-eastern France.