Elachista melanura is a moth in the Elachistidae family. It was described by Meyrick in 1889. It is found in New Zealand. The wingspan is about 13 mm. The forewings are whitish-grey, somewhat irrorated with darker. There is an elongate black dot on the fold before the middle and a second one in the disc above the middle, as well as a third one in the disc at two-thirds. The hindwings are pale whitish-grey.