Heterostomus is a genus of flies in the family Xylophagidae. It includes a single species, Heterostomus curvipalpis, known from Chile. It has a reddish-brown pupa with black spines.
Some authors have placed Heterostomus in its own family: Heterostomidae. Woodley (2011) states that because its larvae are unknown, its family placement within Xylophagidae remains uncertain.