The Malagasy representatives of the large African genus Tricalysia (tribe Coffeeae s.l.) are revised. Three Malagasy species were hitherto recognized in the genus, viz. T. cryptocalyx, T. madagascariensis and T. ovalifolia. In this study two species, T. boiviniana and T. leucocarpa, are transferred from the genus Hypobathrum and seven new species and two new subspecies are described, raising the species number for Tricalysia to a total of twelve. This marked increase in species number is a recurring pattern for many Malagasy genera in systematically badly known families such as Rubiaceae. All the species are described in detail and illustrated, a list of exsiccatae and a distribution map is given. Furthermore, the characters of the Malagasy taxa are compared to those of the continental African species and their infrageneric status is discussed. With the exception of T. ovalifolia, a member of subgenus Empogona, all Malagasy species belong to subgenus Tricalysia. Because of their unisexual flowers, these species cannot be accommodated within one of the four existing sections in subgenus Tricalysia. A new section, Androgyne, is therefore recognized