| Lake Żarnowiec | |
| Location: | Pomorze Voivodeship |
| Coords: | 54.763°N 18.053°W |
| Pushpin Map: | Poland#Poland Pomeranian Voivodeship |
| Inflow: | Piaśnica |
| Outflow: | Piaśnica |
| Basin Countries: | Poland |
| Length: | 7.6km (04.7miles) |
| Width: | 2.6km (01.6miles) |
Lake Żarnowiec is located in the Pomorze Voivodeship. It's 7.6 km long, 2.6 km wide and has a depth of 16 m. The river Piaśnica cuts through it. The Żarnowiec Nuclear Power Plant was supposed to be built next to it. It now serves as the lower reservoir for the Żarnowiec Pumped Storage Power Station.