Thrashers are a paraphyletic group of New World passerine birds related to mockingbirds and New World catbirds. Like these, they are in the family Mimidae. There are 15 species in one large and 4 monotypic genera.
The thrashers do not form a monophyletic clade but are a phenetic assemblage within the family Mimidae. The Mimidae as a whole is made up of two clades, the larger of which contains the Toxostoma thrashers and the monotypic genus Oreoscoptes, and the smaller of which contains the Ramphocinclus, Allenia, and Margarops thrashers. In the larger clade, Toxostoma is sister to all other lineages, with Oreoscoptes sister to Mimus mockingbirds.