The Baiyer River Sanctuary is a nature reserve along the Baiyer River in Western Highlands Province of Papua-New Guinea. It was opened on 13 January 1968 by the then-Australian administration. It has been expanded to a current area of 740 hectares. The reserve lies at elevations of between 800 and 1200 meters. The area of the reserve had been the scene of considerable unrest over years and the main buildings had been burned down.