 While they were previously thought to be close relatives of the genus "Dinichthys" (when they were not synonymized as each other) and grouped together in the family Dinichthyidae, more recent studies have shown that the two taxa represent two very distinct clades within Arthrodira.The reappraisal of "Kiangyousteus" lead to a restructuring of the family, with the inclusions of the benthic, aberrant "Heterosteus" (and the other members of Heterosteidae) as the sister taxon of "Dunkleosteus", and the Late Emsian "Xiangshuiosteus" as the sister taxon of "Eastmanosteus calliaspis" (with the direct implication that "E. calliaspis" does not belong in "Eastmaneosteus"), and the removal of "Westralichthys" from the family (now thought to be the most basal member of the superfamily Dunkleosteoidea, and sister taxon of Panxiosteidae and Dunkleosteidae)

The type genus, "Dunkleosteus", is known from Late Frasnian and Famennian-aged marine strata from Europe, Morocco, and North America.The best known species, "D. terrelli", is famous as the "world's first vertebrate apex predator," and is estimated to be up to in length