Ophiusa trapezium is a moth of the family Erebidae first described by Achille Guenée in 1852.

It is found from the Indo-Australian tropics of India, Sri Lanka to Queensland, the Bismarck Islands and New Caledonia.

A broad diffused sub-marginal fuscous band present.

Forewings with fuscous cell and a submarginal patch.

[2] Larvae have been reared on Melaleuca species (Myrtaceae) and Melastoma malabathricum (Melastomataceae).