The genus Megalyra Westwood, comprising the entire Australian megalyrid fauna, is revised. Eleven new species are described and sixteen species are redescribed. A key to the species and information on their relationships, distribution, and biology is presented. New synonyms are as follows: M. erythropus Cameron, M. szepligetii Bradley, M. kalgoorliensis Froggatt, M. punctata Froggatt, M. punctata rufina Fahringer, M. fasciipennis to Girault, and M. nigricorpus Girault are newly synonymised under M. fasciipennis Westwood : M. variegata Froggatt, M. frenchi Froggatt, M. lyelli Froggart, and M. hirsuta Froggatt are newly synonymised under M. rufipes Erichson: M. fabrei Girault is newly synonymised under M. viridescens Froggart; and M. mutilis Westwood, M. melanoptera Schletterer, and M. mastersi Froggatt are newly synonymised under M. shuckardi Westood. Lectotypes are designated for M. fasciipennis Westwood, M. caudata Szepligeti, M. punctata Froggatt, M. lyelli Froggatt, M. variegata Froggatt, M. frenchi Froggatt, M. lilliputiana Turner, and M. testaceipes Turner. A neotype is designated for M. wagneri Fahringer. Characters supporting the monophyly of Megalyra are discussed, and the species are classified into species-groups