The Philippine species of Medinilla (Melastomataceae) are revised and a total of eighty species are recognized for the Philippine archipelago, one of the centres of diversity of Medinilla. The species exhibit a wide array of forms and highly localized geographic distributions. A systematic study of herbarium specimens revealed the existence of twelve species groups. A key to the species groups and species within each group, descriptions, illustrations, and habitat information are provided. The segregate genera Carionia, Cephalomedinilla, and Hypenanthe are treated here as congeneric with Medinilla. One new species, M. palawanensis, is described. Three new combinations and several reductions, neotypifications, and lectotypifications are proposed.