Bouenza (can also be written as Buenza or Bwenza[2]) is a department of the Republic of the Congo in the southern part of the country.

It borders the departments of Lékoumou, Niari, and Pool, and internationally, the Democratic Republic of the Congo.

Bouenza Department is divided into one commune and ten districts: The population is 363,850 in 2023,[5] and the area is 12,265.4 km².

Among the principal activities are a cement factory in Loutété, sugar cane plantations in Nkayi, and there are reserves of copper, lead and zinc.

Farming includes bananas, palm oil, groundnuts, tobacco and beans.