Mynydd Nodol is a 539m high hill in Snowdonia National Park and lying within the community of Llanycil in the county of Gwynedd in North Wales.

It rises above the southern shores of the reservoir Llyn Celyn about 4 km northeast of its higher neighbour Arenig Fawr.

The hill is formed from the acid ash-flow tuffs of the Llyn Conwy Formation of the Ordovician age Aran Volcanic Group.

[1] There are abandoned manganese mining levels and tips on the hill's northern and western flanks, recorded as being worked intermittently from 1867 for around 40 years.

An unfenced minor public road running northwest from Bala fringes the southwestern edge of the hill.