The flat wasp genus Megaprosternum (Scleroderminae) is studied and revised. Fifteen species are recognized, including five previously described ones: M. cleonarovorum, M. longiceps, M. neolongiceps, M. norfolcensis, and M. pentagonal. Additionally, 10 new species are described and illustrated: M. aka sp. nov. and M. bayaka sp. nov. (both from the Central African Rep.), M. chamorro sp. nov., M. hmong sp. nov., M. kariri sp. nov., M. kayin sp. nov., M. navatu sp. nov., M. nuaulu sp. nov., M. samburu sp. nov., and M. wakawaka sp. nov. An emended diagnosis and a detailed discussion regarding the morphological diagnostic characters of this genus and its species, along with comments about the distribution pattern of Megaprosternum, are also presented. Additionally, a taxonomic key for males and females of all species is provided.