Orocrambus aethonellus is a moth in the family Crambidae. It was described by Edward Meyrick in 1883. It is endemic to New Zealand. O. aethonellus has been recorded from the South Island. The habitat consists of sandhills and bogs at sea level, up to altitudes of about 1,200 meters.
O. aethonellus was first described by Edward Meyrick in June 1882 and named Crambus aethonellus. Meyrick gave a fuller description of this species in May 1883. The lectotype specimen, collected at Mount Hutt by R. E. Fereday, is held at the Natural History Museum, London.
The wingspan is 13âÂÂ20 mm for males and 15âÂÂ21 mm for females. Adults have been recorded on wing from late October to late January.