Taxonomy of the Texas representatives of the genus Xanthonia Baly, 1863 (Coleoptera: Chrysomelidae: Eumolpinae) is reviewed. A total of 12 species are recognized in Texas, including seven that are described as new: X. hirsuta Weisman, X. marquai Riley Quinn, X. nitida Weisman, X. parva Riley Quinn, X. picturata Weisman Riley, X. querci Weisman, and X. texana Weisman. A key to the species recorded from Texas is given together with habitus and male genitalia figures, plant associations, and Texas range maps. Adult seasonality and plant preference data are graphically presented for abundant central Texas species. Previous Texas records of X. striata Staines Weisman are based on misidentifications of X. angulata Staines Weisman.
Keywords: Coleoptera, leaf beetle, plant association, seasonality, taxonomy, United States of America.