| Llyn Cwm Bychan | |
| Pushpin Map: | Wales Gwynedd |
| Location: | Gwynedd, North Wales |
| Coords: | 52.8617°N -5.6°W |
| Lake Type: | natural |
| Outflow: | River Artro |
| Basin Countries: | Wales |
| Elevation: | 180m (590feet) |
Llyn Cwm Bychan is a lake in north Wales, and is one of the sources of the River Artro which flows south westwards through Llanbedr and onwards to the sea.It is located in the Rhinogydd mountains of Snowdonia.