Zetesima portentosa is a moth in the family Depressariidae.

There is a strong costal fold reaching nearly to the middle of the wing, which contains a cluster of long, broad, iridescent scales and there is a round black dot at the end of the cilia, edged by ochreous scales.

A black, ill-defined streak is found on the outer and upper edge of the cell and there is a series of ill-defined, black, marginal spots around the costal, apical, and terminal edges.

The hindwings are blackish brown with a light ochreous costal space covered by the forewings.

This article on a moth of the family Depressariidae is a stub.