The Kasaï region (also referred to as the Greater Kasaï region, Greater Kasaï, Grand Kasaï, or simply Kasaï) is a geographic and cultural region in south-central Democratic Republic of the Congo. Once a single province, it now comprises the provinces of Kasaï Province, Kasaï-Central, Sankuru, Kasaï-Oriental, and Lomami Province. It shares its name with the Kasai River.
Historically, the Kasaï region has been a stronghold for the Union for Democracy and Social Progress (UDPS) party. As an opposition stronghold, it experienced both political and economic marginalization by the central government. This long-running resentment of the central government's remoteness and corruption exploded into a rebellion, triggered by the official rejection of a local chief, Kamwina Nsapu, who in August 2016 was killed by security forces. After UDPS candidate Félix Tshisekedi's victory in the 2018 presidential election, most militia members surrendered and returned to their communities of origin.