Hyposmocoma auropurpurea is a species of moth of the Cosmopterigidae family. It is endemic to Oahu. The type locality are the Waianae Mountains. The length of the forewings 4.8–5 mm for males and 5.2–5.5 mm for females. The species is unique among Hyposmocoma species because it has metallic purple wings with a narrow, diagonal orange band near the wing apex. The larval case is dark brown, smooth, 7–9 mm in length and 1.7–2 mm wide. Case-making larvae have been collected from October to April. Larvae were found in leaf litter, but also on leaves of living plants, such as Pittosporum species.