Kozani (Greek: Περιφερειακή Ενότητα Κοζάνης, romanized: Perifereiakí Enótita Kozánis) is one of the regional units of Greece.

Kozani borders the regional units of Kastoria to the west and northwest, Florina to the north, Pella to the northeast, Imathia and Pieria to the east, Larissa (part of Thessaly) to the southeast, and Grevena to the south.

The Kozani Prefecture was created in 1915 and also included the present Florina, Grevena and the Kastoria regional units.

Nowadays, Kozani is still among the most prosperous areas of the Greek province, but for a different reason, its rich mining industry.

In the regional unit of Kozani there is also the artificial lake and hydroelectric dam of Polyfytos, which further contributes to the electricity production of Greece.

The region's vast industrial advancement in a short period of time has raised environmentalist concerns.