Sarn Meyllteyrn is a village and former civil parish (known at the time as Mellteyrn) in the Welsh county of Gwynedd.

It is in the west of the Llŷn Peninsula (Welsh: Penrhyn Llŷn), 8.4 miles (13.5 km) west of Pwllheli and 24.3 miles (39.2 km) south-west of Caernarfon.

The parish was abolished in 1934 and divided between the communities of Botwnnog and Tudweiliog.

Primary education is provided by Ysgol Pont y Gôf, in the nearby village of Botwnnog.

The school is in the Ysgol Botwnnog catchment area and this is where the majority of pupils go on to complete secondary education.