The chestnut-flanked white-eye (Zosterops erythropleurus/红胁绣眼) is a species of bird in the Zosteropidae family. It is found in Cambodia, China, Hong Kong, Japan, North Korea, South Korea, Laos, Myanmar, Russia, Thailand, and Vietnam. The species is migratory, breeding in northern China and migrating to Southeast Asia in the winter. It is the most migratory species of white-eye. It breeds in poplar, alder and willow forests, thickets and groves, and winters in deciduous and evergreen forests, usually above 1000 m.