Kadéï, Kadéi, Kadeï and Kadei redirect here. For the province or region in Cameroon, see Kadey

The Kadéï River is a tributary of the Sangha River that flows through Cameroon and the Central African Republic. Its total drainage basin is 24,000 km². The river rises from the eastern Adamawa Plateau, southeast of Garoua-Boulaï (5°53′50″N 14°33′30″E / 5.89722°N 14.55833°E / 5.89722; 14.55833 (Kadéï River headwaters) in Cameroon's East Province. The Kadéï is swelled by two tributaries, the Doumé at Mindourou (4°7′45″N 14°34′22″E / 4.12917°N 14.57278°E / 4.12917; 14.57278 (Doumé Rvier mouth)) and the Boumbé (4°6′45″N 15°7′10″E / 4.11250°N 15.11944°E / 4.11250; 15.11944 (Boumbé River mouth)), before flowing east into the Central African Republic. At Nola (3°31′10″N 16°2′35″E / 3.51944°N 16.04306°E / 3.51944; 16.04306 (Kadéï River mouth)), the Kadéï meets the Mambéré and becomes the Sangha. The Kadéï is part of the Congo River basin.