The first record of the genus Semia Matsumura (Cicadidae: Cicadinae, Cicadini) from Vietnam is presented. One new species, Semia spinosasp. n., is described from southern Vietnam. Photos of the adult, illustrations of the male genitalia, a distribution map and biological data are provided. A key to the species of Semia based on the male adults is also given.
Keywords: Auchenorrhyncha; Cicadina; New record genus; Semia spinosa; morphology.