The Bantu expansion, a major topic in African archaeology and history, is widely assumed to correlate with the spread of farming, but archaeological data on the subsistence of these putative early Bantu speakers are very sparse. However, finds of domesticated pearl millet (Pennisetum glaucum) in southern Cameroonian archaeological sites, dated between 400 and 200 BC, open new perspectives on the history of agriculture in the Central African rain forest. Linguistic evidence suggests that pearl millet was part of early agricultural traditions of Bantu speakers, and has to a great extent been distributed during the course of their expansion over large parts of western Bantu-speaking Africa, possibly even originally from their homeland in the Nigerian-Cameroonian borderland. In combining archaeobotanical, palaeoenvironmental and linguistic data, we put forward the hypothesis that an agricultural system with pearl millet was brought into the rain forest during the first millennium BC, and that its pread across Central Africa coincided with the dispersal of certain Bantu language subgroups.