The Hewitson's Olivewing (Nessaea hewitsonii) is a species of butterfly of the Nymphalidae family. It is common in a broad range of the Amazon basin including the eastern slopes of the Andes mountain range. It is found in high evergreen tropical forest, semi-deciduous tropical forest, and riverine forest. The length of the wings is 33–40 mm for males and 36–41 mm for females. The upperside of the males is dark brown, with bright sky blue diagonal bands on the forewings and blue markings on the hindwings.