Abstract Limacodidae (Zygaenoidea), a mostly pantropical family of 1,800+ species, is known for sluglike caterpillars with suckers below rather than typical prolegs. They typically have either venomous spines (nettles) or a smooth surface (gelatines) above. Previous limacodid phylogenies were of limited geographic scope or narrow taxonomic focus, thus unable to show the family’s internal relationships comprehensively. Our phylogenetic hypotheses include 95 genera and 125 species of Limacodidae (stat. nov.) of worldwide distribution, doubling genera, and tripling species numbers represented from previous studies. Additionally, 14 species in other zygaenoid families and 6 outside Zygaenoidea are included. In contrast to other works based on independent analysis of either molecular or morphological data, our limacodid-focused trees are the first ones to combine molecular data with morphological characters from adults and immature stages. Resulting topologies are based on 1 mitochondrial and 6 nuclear genes, totaling 5,153 base pairs, and 122 morphological characters (5,275 characters in total). Our trees support the monophyly of Zygaenoidea and a new subfamily arrangement of a monophyletic Limacodidae: Crothaeminae (stat. rev.), Dalcerinae (stat. nov.), Chrysopolominae, and Limacodinae (stat. nov.). Two tribes recognized in Limacodinae, and previous subfamilies in Dalceridae and Chrysopolomidae are reduced to tribal rank. Synapomorphies of all life-stage characters are presented for Limacodidae and other family groups of Zygaenoidea. The total evidence topology is congruent with many features of egg, larval, and adult stage evolution. With new larval ontogenetic information, we present a hypothesis on how ontogeny and other modifications played a significant role in Limacodidae diversification through various defensive strategies.