Orocrambus aethonellus is a moth in the Crambidae family. It was described by Meyrick in 1883. It is found in New Zealand, where it 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. The wingspan is 13–20 mm for males and 15–21 mm for females. Adults have been recorded on wing from late October to late January.