| Lake Roś | |
| Location: | Masurian Lake District, Poland |
| Inflow: | Swięcek and Konopka |
| Pushpin Map: | Warmian-Masurian Voivodeship |
| Outflow: | Pisa |
| Basin Countries: | Poland |
| Area: | 18.88km2 |
| Depth: | (mean) |
| Frozen: | For period 1977–1992 usually between 21 December and 15 March with maximum ice thickness |
Lake Roś (Polish: Jezioro Roś, German: Roschsee) is a lake in the Masurian Lake District of the Warmian-Masurian Voivodeship of Poland. This S-shaped glacial lake has an area of and a maximum depth of 31.8m (104.3feet). The Swięcek and Konopka rivers flow into the lake, while the Pisa River flows out of it. The largest town on the lake is Pisz.