Phylogenetic relationships among birds of prey in the subfamily Buteoninae are not fully established but are of particular interest because the Buteoninae constitute one of the largest accipitrid subgroups and include multiple species of conservation concern. Genera previously included within the Buteoninae are Buteo, Leucopternis, Buteogallus, Harpyhaliaetus, Busarellus, Parabuteo, Geranoaetus, Geranospiza, Ictinia, Rostrhamus, Kaupifalco, and Butastur. We analyzed representatives from all buteonine genera and most non-Buteo (i.e., "sub-buteo") species with >3,000 bases of nuclear and mitochondrial DNA and found non-monophyly for the nominal genera Buteo, Buteogallus, and Leucopternis. The Old World Lizard Buzzard (Kaupifalco monogrammicus) is not closely related to buteonine taxa but is sister to goshawks in the genera Melierax, Micronisus, and Urotriorchis. Another Old World genus, Butastur, is sister to the clade including all other buteonine genera mentioned above. Investigation of several "superspecies" complexes within the genus Leucopternis revealed non-monophyly for the four subspecies of White Hawk (L. albicollis). On the basis of mitochondrial data, L. a. albicollis forms a clade with L. polionotus, whereas L. a. costaricensis, L. a. ghiesbreghti, and L. a. williaminae form a clade with L. occidentalis. Among taxa included as outgroups, we found two species in the genus Circus to be clearly nested within a clade of Accipiter spp.