| Jonsvatnet | |
| Pushpin Map: | Trøndelag#Norway |
| Pushpin Label Position: | bottom |
| Pushpin Map Caption: | Location of the lake |
| Coordinates: | 63.3655°N 10.582°W |
| Location: | Trondheim, Malvik, Trøndelag |
| Outflow: | Vikelva |
| Basin Countries: | Norway |
| Area: | 14.26km2 |
| Reference: | NVE |
Jonsvatnet is a lake in Trøndelag county, Norway. Most of the lake is in the eastern part of the municipality of Trondheim, with a very small part of the shoreline belonging to Malvik municipality. The lake is the main source for drinking water for the city of Trondheim.[1]