Nias people are an ethnic group native to Nias, an island off the west coast of North Sumatra, Indonesia. In the Nias language, the Nias people are known as Ono Niha, which means 'descendants of humans'. Nias island is known as Tanö Niha, with Tanö meaning 'land' in the Nias language.

Nias is an island located off the western coast of Sumatra, Indonesia. Nias is also the name of the archipelago of which the island is the centre, but also includes the Batu Islands to the southeast and the small Hinako Islands to the west. Nias Island covers an area of 5,573.27 km2 (2,151.85 sq mi). It is mostly a lowland area rising to around 800 m (2,600 ft) above sea level. There were 756,338 inhabitants on the island at the 2010 Census; at the 2015 Intermediate Census this had risen to 798,506 and the 2020 Census resulted in a total of 880,550. The official estimate as of mid-2023 was 930,294.