The Sittaung ( ; formerly, the Sittang or Sittoung) is a river in south central Myanmar in Bago Division. The Pegu Range separates its basin from that of the Irrawaddy. The river originates at the edge of the Shan Plateau southeast of Mandalay, and flows southward to the Gulf of Martaban. Its length is 420 km and its mean annual discharge is around 50 cubic kilometers per year.