Ethmia umbrimarginella is a moth in the family Depressariidae.
It is found in southern Arizona and New Mexico in the United States.
The length of the forewings is . The ground color of the forewings is dark slate gray. The immediate costal edge is dirty white up to the distal one-fourth. The ground color of the hindwings is white, with a broad dark gray margin around the apical, terminal and dorsal areas. Adults have been recorded in February.