Elachista helonoma is a moth in the Elachistidae family. It was described by Meyrick in 1889. It is found in New Zealand. The wingspan is 8–10 mm. The forewings are whitish, more or less irrorated with ochreous, especially on the dorsal half. There is a slender ochreous-fuscous median longitudinal streak from near the base to the middle, and a second from above the extremity of the first to near the apex. There is also a fuscous dot beneath the apex of first the streak and the inner margin is more or less obscurely brownish towards the base. The hindwings are pale grey.