Petín is a municipality in the province of Ourense, within the autonomous community of Galicia in northwestern Spain. It belongs to the comarca (district) of Valdeorras.
The municipality covers an area of 31 square kilometres and has a population of 1,131. It is one of the smaller municipalities of the Valdeorras comarca, a district known within Galicia for its slate quarrying and wine production.
As a Galician municipality, Petín sits within a region characterised by a distinct cultural and linguistic identity, with both Galician and Spanish in official use.