| Sy | |
| Commune Status: | Commune |
| Image Coat Of Arms: | Blason Sy.svg |
| Arrondissement: | Rethel |
| Canton: | Vouziers |
| Insee: | 08434 |
| Postal Code: | 08390 |
| Mayor: | Bruno Deswaene[1] |
| Term: | 2020 - 2026 |
| Intercommunality: | Argonne Ardennaise |
| Coordinates: | 49.5161°N 4.8716°W |
| Elevation M: | 180 |
| Elevation Min M: | 176 |
| Elevation Max M: | 267 |
| Area Km2: | 7.97 |
Sy (in French pronounced as /si/) is a commune in the Ardennes department in northern France.