Ethmia nadia is a moth in the family Depressariidae. It is found in California.
The length of the forewings is . The ground color of the forewings is dark gray, but paler distally. There are dark spots adjoining a longitudinal streak. Adults are on wing from March to May (in southern California) and from June to July (in Siskiyou County).
The larvae feed on Phacelia ramosissima.