| Osse | |
| Pushpin Map: | France#France Nouvelle-Aquitaine |
| Source1 Location: | Plateau de Lannemezan |
| Source1 Coordinates: | 43.3383°N 0.3269°W |
| Mouth Coordinates: | 44.1208°N 0.2803°W |
| Subdivision Type1: | Country |
| Length: | 120.3km (74.8miles) |
| Source1 Elevation: | 350m (1,150feet) |
| Mouth Elevation: | 42m (138feet) |
| Discharge1 Avg: | 2.62m3/s |
| Basin Size: | 600km2 |
The Osse (in French pronounced as /ɔs/) is a 120km (80miles) long river in southwestern France, right tributary of the river Gélise. Its source is in the Hautes-Pyrénées, 2km (01miles) southeast of the village Bernadets-Debat, in the Plateau de Lannemezan. It joins the river Gélise 5km (03miles) southwest of the town Nérac.
Its course crosses the following départements and communes: