The Kokemäenjoki ("Kokemäki River", sv|Kumo älv) is a river in southwestern Finland.
The river originates at Lake Liekovesi in the Pirkanmaa region, and flows to the Gulf of Bothnia at Pori in the Satakunta region. Primary tributaries of Kokemäenjoki are the Loimijoki, Kauvatsanjoki and Harjunpäänjoki rivers. Kokemäenjoki river delta is the largest river delta in the Nordic countries and is an important wildlife area.