Leptofoenus is a genus of wasp in the family Pelecinellidae found in South America, Central America, and southern North America.

[1][2] The genus contains five living species and one extinct species known from early Miocene Burdigalian stage Dominican amber deposits on the island of Hispaniola.

[1] With body sizes ranging from 11–27 millimetres (0.43–1.06 in) Leptofoenus species are larger than nearly all other species in Chalcidoidea.

[1] The genus bears a notable resemblance to the wasp families Pelecinidae, Gasteruptiidae, and Stephanidae.

[1] All six known species are restricted to the western Hemisphere, most being found in South America and only one reaching North America.