Leptofoenus is a genus of wasp in the family Pteromalidae, the type genus subfamily Leptofoeninae found in South, Central, and southern North America. The genus contains five living species and one extinct species known from early Miocene Burdigalian stage Dominican amber deposits on the island of Hispaniola. With body sizes ranging from 11–27 millimetres (0.43–1.06 in) Leptofoenus species are larger than nearly all other species in Pteromalidae. The genus bears a notable resemblance to the wasp families Pelecinidae, Gasteruptiidae, and Stephanidae.