Mesodma is an extinct genus of mammal, a member of the extinct order Multituberculata within the suborder Cimolodonta, family Neoplagiaulacidae. It lived during the upper Cretaceous and Paleocene Periods of what is now North America. This genus has been the subject of much revision, and has also been known in part as Cimexomys, Cimolomys, Halodon, Parectypodus, and Ptilodon.