Apateodus Woodward (Teleostei: Aulopiformes) is a Late Cretaceous bony fish that is known by only a few cranial specimens. On the basis of a previously unreported partial skeleton of Apateodus from the Smoky Hill Chalk Member (lower Campanian portion) of the Niobrara Chalk in western Kansas, U.S.A., here, we emend the diagnosis for the genus and describe a new species, A. busseni. The specimen substantiates the presence of Apateodus in the North American Western Interior Seaway during the early Campanian and marks the fifty-fifth osteichthyan fish so far recognized from the Niobrara Chalk of Kansas. Like another species of Apateodus, A. striatus (Agassiz), Apateodus busseni sp. nov. was a medium-sized (ca. 40 cm TL), slender pelagic fish, that was likely capable of fast swimming.