| Attignat-Oncin | |
| Commune Status: | Commune |
| Image Coat Of Arms: | Blason ville fr Attignat-Oncin (Savoie).svg |
| Arrondissement: | Chambéry |
| Canton: | Le Pont-de-Beauvoisin |
| Insee: | 73022 |
| Postal Code: | 73610 |
| Mayor: | Thomas Ilbert[1] |
| Term: | 2020 - 2026 |
| Intercommunality: | CC Lac d'Aiguebelette |
| Coordinates: | 45.5092°N 5.7764°W |
| Elevation Min M: | 381 |
| Elevation Max M: | 1427 |
| Area Km2: | 18.46 |
Attignat-Oncin (in French pronounced as /atiɲa ɔ̃sɛ̃/; Attigna Onshin) is a commune in the Savoie department in the Auvergne-Rhône-Alpes region in south-eastern France.