Eudonia octophora is a species of moth of the Crambidae family. It is known from New Zealand. The wingspan is 22–24 mm. The forewings are brownish-ochreous, irrorated with dark fuscous, forming dark lines on the veins. There are a few white scales. The first line is pale, dark-margined posteriorly and the second line is whitish and also dark-margined. The hindwings are ochreous-grey-whitish, with the postmedian line and apex greyer. Adults have been recorded on wing in December, January and March.