Errezil is a town in the province of Gipuzkoa, in the autonomous community of the Basque Country in northern Spain. It is a small municipality within the Basque region, situated in the north of the country.
The town is notable for its high level of Basque language use. According to the 2016 Basque sociological survey, Errezil had the largest percentage of Basque speakers of any municipality in the Basque Country, with over 90% of respondents reporting Basque as their first language and/or reporting that they spoke Basque at home.