"Achillobator" is classified as a dromaeosaurid taxon, more specifically within the Eudromaeosauria, a group of hypercarnivore dromaeosaurids that were mainly terrestrial instead of arboreal or amphibious. In most cladistic analyses "Achillobator" is recovered as a close relative of "Dromaeosaurus" and "Utahraptor", although it is often considered to be the sister taxon of the latter. The stocky and short hindlimb ratio of "Achillobator" indicates that it was not cursorial—an animal adapted for speed or to maintain high speeds—moreover, the robust morphology of the maxilla suggests a predatory behavior based on large-sized prey.