Kamashi is a zone in the Benishangul-Gumuz Region of Ethiopia. It covers part of the southern bank of the Abay and the valley of the Didessa Rivers. The Zone is bordered on the south and east by the Oromia Region, on the west by the Assosa and Sudan, and on the north by Metekel and the Amhara Region, which lie on the further bank of the Abay. The majority ethnic group in the zone is the Gumuz people, with significant Oromo and Amhara minorities as well.
Rivers in Kamashi include the Didessa.