The Colubroidea includes all venomous and some nonvenomous snakes, many of which have extraordinary dental morphology and functional capabilities. It has been proposed that the ancestral condition of the Colubroidea is venomous with tubular fangs. The venom system includes the production of venomous secretions by labial glands in the mouth and usually includes fangs for effective delivery of venom. Despite significant research on the evolution of the venom system in snakes, limited research exists on the driving forces for different fang and dental morphology at a broader phylogenetic scale. We assessed the patterns of fang and dental condition in the Lamprophiidae, a speciose family of advanced snakes within the Colubroidea, and we related fang and dental condition to diet. The Lamprophiidae is the only snake family that includes front-fanged, rear-fanged, and fangless species. We produced an ancestral reconstruction for the family and investigated the pattern of diet and fangs within the clade. We concluded that the ancestral lamprophiid was most likely rear-fanged and that the shift in dental morphology was associated with changes in diet. This pattern indicates that fang loss, and probably venom loss, has occurred multiple times within the Lamprophiidae. There is also evidence that front fangs arose from a rear-fanged condition, and this has occurred independently more than once within the family. Our findings provide insight into fang and dental condition in relation to diet and support the hypothesis of a venomous ancestor for the Lamprophiidae.