Ethmia brevistriga is a moth in the Depressariidae family. It is in California, United States. The length of the forewings is 4.7-6.4 mm. The ground color of the forewings is dark brown; with a distinct white line. The ground color of the hindwings is dark brown, but the costal area is paler. Subspecies aridicola has a darker ground color owing to a reduction of the whitish overscaling, especially on the costal half. Adults are on wing from March to mid-May. The larvae feed on Phacelia distans. Subspecies aridicola only feeds on Phacelia distans var. australis.