Voio (Greek: Βόιο) is a municipality in the Kozani regional unit, Greece. The seat of the municipality is the town Siatista. It was named after the Voio mountains.
The municipality Voio was formed at the 2011 local government reform by the merger of the following 5 former municipalities, that became municipal units:
The province of Voio (Greek: Επαρχία Βοΐου) was one of the provinces of the Kozani Prefecture. Its territory corresponded with that of the current municipality Voio. It was abolished in 2006.