One new genus, Kalops, and two new species, K. monophrys and K. diophrys, are described from the Carboniferous (Namurian) marine Bear Gulch limestone of Montana (USA). The most conspicuous features of these elongate fusiform actinopterygians consist of one or two rows of anamestic supraorbital bones, a mosaic of suborbitals, and the presence of two rows of extrascapulars in one species. Discussions of their anatomical, morphometrical, and growth characters result in their placement in the same genus. Comparisons with other Palaeozoic actinopterygians show that Kalops is a Palaeoniscimorpha (=basal Actinopteri sensu Patterson).