Ethmia lassenella is a moth in the Depressariidae family. It is found in the United States in California, Arizona, Nevada and Utah. The length of the forewings is 7.8-8.3 mm. The ground color of the forewings is steel gray including the fringe. There are two bright red-orange spots and five smaller black spots. The ground color of the hindwings is white with a broad black, moderately well defined marginal band. Adults are on wing from mid-March to mid-April.