Ethmia oterosella is a moth in the Depressariidae family. It is found in Cuba. The length of the forewings is 6.7 to 8 millimetres (0.26 to 0.31 in). The ground color of the forewings is divided by a line. The dorsal half is whitish and the costal half blackish along the line, blending to brown through the cell and to whitish at the costa. The terminal area is mostly whitish brown. The ground color of the hindwings is whitish, becoming pale brownish distally. The larvae possibly feed on Stegnospermum halimifolia or Trichostigma octandrum.