A new genus, Wallabicoris, is described from Australia with 37 included species, all described as new. Host plants for 29 species of Wallabicoris are recorded in the families Asteraceae, Boraginaceae, Fabaceae (Papilionoideae), Lamiaceae, Rhamnaceae, Sterculiaceae, and Thymelaeaceae. Maps organized on the basis of host association are presented. A phylogenetic analysis based on 53 morphological characters is presented for all species and seven outgroups. An additional analysis for 25 in-groups and the seven outgroups is presented in which the morphological characters are combined with about 470 bases of 16S mtDNA. These analyses show Wallabicoris to be monophyletic, as are several species groups within the genus. Monophyletic groups of species feeding on the Rhamnaceae and Lamiaceae received strong support, suggesting radiations on those plant lineages. Distributional patterns are examined within the context of the larger Australian fauna and with regard to the distributions of host taxa.