| Llyn Nantlle Uchaf | |
| Pushpin Map: | Wales Gwynedd |
| Location: | Wales |
| Coords: | 53.0542°N -4.2178°W |
| Lake Type: | natural |
| Outflow: | Afon Llyfni |
| Basin Countries: | United Kingdom |
| Area: | 80acres |
| Cities: | Nantlle |
cy|'''Llyn Nantlle Uchaf'''|Upper Nantlle Lake|italic=no is a lake in the Nantlle Valley, Gwynedd, Wales. The lake forms the foreground in Richard Wilson's painting "Snowdon from Llyn Nantlle".[1]
Llyn Nantlle Isaf (Lower Nantlle Lake) no longer exists as it was drained to protect the slate works.[2]