| Groissiat | |
| Commune Status: | Commune |
| Arrondissement: | Nantua |
| Canton: | Nantua |
| Insee: | 01181 |
| Postal Code: | 01100 |
| Mayor: | Patricia Deguerry[1] |
| Term: | 2020 - 2026 |
| Intercommunality: | Haut-Bugey Agglomération |
| Coordinates: | 46.2222°N 5.6069°W |
| Elevation M: | 530 |
| Elevation Min M: | 507 |
| Elevation Max M: | 940 |
| Area Km2: | 6.32 |
Groissiat (in French pronounced as /ɡʁwasja/) is a commune in the Ain department in eastern France.