This article reviews evidence from biogeography, palynology, geology, historical linguistics, and archaeology and presents a new synthesis of the paleoclimatic context in which the early Bantu expansion took place. Paleoenvironmental data indicate that a climate crisis affected the Central African forest block during the Holocene, first on its periphery around 4000 BP and later at its core around 2500 BP. We argue here that both phases had an impact on the Bantu expansion but in different ways. The climate-induced extension of savannas in the Sanaga-Mbam confluence area around 4000–3500 BP facilitated the settlement of early Bantu-speech communities in the region of Yaoundé but did not lead to a large-scale geographic expansion of Bantu-speaking village communities in Central Africa. An extensive and rapid expansion of Bantu-speech communities, along with the dispersal of cereal cultivation and metallurgy, occurred only when the core of the Central African forest block was affected around 2500 BP. We claim that the Sangha River interval in particular constituted an important corridor of Bantu expansion. With this interdisciplinary review, we substantially deepen and revise earlier hypotheses linking the Bantu expansion with climate-induced forest openings around 3000 BP.