The Odontiinae Guenee, 1854 (Lepidoptera: Pyraloidea: Crambidae) comprises two tribes: Eurrhypini Leraut and Luquet, 1983, and Odontiini, based on the presence or absence of a complex genitalic apparatus. The former tribe is subjected to cladistic parsimony analysis, including 122 terminals, 2 outgroups, and 116 characters of adult morphology, tympanal organs, genitalia, and larval habits. Most characters are new and are illustrated. The genitalic apparatus is inferred to be a synapomorphy of the Odontiinae with multiple subsequent losses, and the Odontiini as previously deliminted is polyphyletic. The fine structure of the lamelliform and squamiform structure is investigated and compared to similar structures in Noordinae. The tropical and certain temperate genera are diagnosed based on synapomorphies of the included species, and a key to genera based on adult morphology is given.