The Chaun River (Russian: Чаун) is a stream in Far East Siberia. It flows roughly northwards, passing through the sparsely populated areas of the Siberian tundra. The Chaun River flows into the East Siberian Sea at the Chaunskaya Bay, 100 kilometres (62 mi) south of Pevek city. Its mouth is close to the mouth of the Palyavaam River.
Its most important tributaries are the Ugatkyn from the left side and the Malyy Chaun from its right side. The Chaun river gives the Chaunskaya Guba (or Bay) its name.