Eudonia leptalea is a moth in the Crambidae family. It was described by Meyrick in 1885. It is found in New Zealand, including the Chatham Islands. The wingspan is 16–19 mm. The forewings are whitish-ochreous or ochreous-grey, irrorated with dark fuscous or black, and densely irrorated with whitish. The markings are variable in distinctness and may sometimes be almost obsolete. The first line is white, margined by dark posteriorly. The second line is white and margined by dark. The hindwings are whitish-grey. The postmedian line is darker and the hindmargin is suffused with darker grey. Adults have been recorded on wing from January to March.