A taxonomic revision of the genus Buxus L. (Buxaceae) in Madagascar and the Comoro Islands is presented. Reevaluation of morphological characters allow us to recognize nine species (all in Madagascar, and two also occurring in the Comoros), seven of which are described as new. Ecogeographic features of each species in relation to bioclimate and substrate geology are discussed, and a preliminary conservation assessment is calculated according to IUCN Red List criteria.