Ompok brevirictus can be distinguished from all Southeast Asian congeners, except for O. siluroides and O. miostomus, in having melanophores on the tympanic region forming a prominent black spot (vs. tympanic region dark, but without any melanophores forming a distinct spot). It differs from O. siluroides and O. miostomus in having an evenly convex predorsal profile (vs. with a concavity posterior to orbit) and a more prominent lower jaw that is more broadly curving. Ompok brevirictus additionally differs from O. siluroides in having the mouth rictus separated from the anterior orbital margin by a distance of more than one-third (vs. less than one-third) eye diameter (4.2–5.2% HL vs. 3.2–3.7) and lacking (vs. possessing) a distinct dark wedge-shaped spot on base of the caudal fin (Ref. 82371).