Moel Eilio is a mountain in Snowdonia, North Wales, that is situated approximately 3 miles north-west of Snowdon itself. It has two subsidiary tops, Foel Gron and Foel Goch (Eilio). The average annual temperature of the mountain is around 6 °C (43 °F). During the winter season, some significant accumulations of snowfall is known to take place on Moel Eilio, due to its relatively flat, grassy slopes.

A popular ascent starts from Llanberis and climbs by way of Bwlch y Groes and then the north ridge of the hill.

Moel Eilio, Foel Gron, Foel Goch and Moel Cynghorion form a curved ridge tracking generally south-west towards Snowdon and can provide a less common route to ascend Snowdon.

A small lake lies below the summit; Llyn Dwythwch.