Underwing moths in the genus Catocala Shrank are among the most charismatic Lepidoptera. Catocala is also one of the most diverse genera in the speciose family Erebidae, but a phylogenetic framework for the genus is lacking. We reconstruct the first comprehensive molecular phylogeny for Catocala based on 685 anchored hybrid enrichment loci sampled from 173 species. Phylogenetic analysis unambiguously recovers Catocala and Catocala + Ulotrichopus as monophyletic with strong support and resolves many backbone relationships within Catocala. Our results confirm the classification of previously proposed taxonomic subgroups of Catocala, including seven based on recent molecular/morphological evidence, and ten based on early twentieth-century morphological research. Mapping of larval host plant use onto the tree shows Fabaceae to be the likely ancestral host plant family for Catocala (96.3% probability) and Catocala + Ulotrichopus (83.9% probability). There were at least 18 independent larval host plant shifts to nine plant families, the most common shift being from Fabaceae to Fagaceae. Larval host plant use appears to have played a critical role in the evolutionary history of Catocala, with several rapid diversification events propelled by shifts to novel larval host plants, particularly in the North American Catocala fauna.