Llanberis (Welsh: [ɬanˈbɛrɪs] ^ⓘ) is a village, community and electoral ward in Gwynedd, northwest Wales, on the southern bank of the lake Llyn Padarn and at the foot of Snowdon, the highest mountain in Wales. It is a centre for outdoor activities in Snowdonia, including walking, mountaineering, climbing, mountain biking and pony trekking, as well as water sports such as scuba diving. The community includes Nant Peris.

Llanberis takes its name from Saint Peris, an early Welsh saint. It is twinned with the Italian town of Morbegno in Lombardy.

The ruins of Dolbadarn Castle, which were painted by Richard Wilson and J. M. W. Turner, stand above the village. The 13th century fortress was built by Llywelyn the Great and is a grade I listed building.

The church of St Padarn is grade II* listed, as is the chapel of Capel Coch.

In the 18th century Llanberis was the home of the legendary strong woman Marged ferch Ifan.

The population of Llanberis in 2021 was 2,023.

According to the United Kingdom Census 2021, 69.5 per cent of all usual residents aged 3+ in Llanberis can speak Welsh. 79.6 per cent of the population noted that they could speak, read, write or understand Welsh. The 2011 census noted 74.7 per cent of all usual residents aged 3 years and older in the village could speak Welsh.

As of October 2018, approximately 56 per cent of pupils in the village's primary school (Ysgol Dolbadarn) spoke Welsh at home.