Ethmia nigroapicella, commonly known as the kou leafworm, is a moth of the family Depressariidae. It is found in Madagascar, the Seychelles, India, Assam, Burma, Samoa, the Philippines, Hawaii, Taiwan, Japan and Australia.
The wingspan is . The forewings are overlaid with fifteen black dots on a grey background and a row of seven marginal dots. The hindwings are orange-yellow, but the apical patch is dark brown and covers one-seventh of the hindwing.
The larvae feed on Ehretia species (including Ehretia dicksoni var. japonica, Ehretia laevis and Ehretia buxifolia), as well as on Cordia subcordata and Cordia sebestena.
This moth figures on a 25-cent stamp of Kiribati from 1980.