Herons (Aves: Ardeidae) are a cosmopolitan family of birds that comprises ~65 species and is found on all continents except Antarctica. Despite being well-studied by ornithologists, phylogenetic relationships within the family are uncertain. For example, the earliest diverging lineages have not been confidently identified, and the monophyly of some genera has been questioned. Here, I present the results of a molecular phylogenetic analysis of herons that includes ~70 percent of species diversity. Analyses of thousands of genomic loci yielded a fully resolved and well-supported phylogeny for the herons. Phylogenetic relationships were broadly congruent across all analytical methods and clarified the composition and placement of several genera that have been traditionally difficult to place. For example, I identified the tiger-herons as the sister-group to all other herons and recovered non-monophyly for some tribes (Nycticoracini and Egrettini) and genera (e.g. Gorsachius and Ixobrychus).