The Oldzho (Russian: Ольджо; Yakut: Олдьо, Olco), also known as Oldyo (Ольдё) or Olduo (Олдьуо), is a river in the Verkhoyansk District, Sakha Republic, Russia. It is a right tributary of the Yana.
The length of the river is 330 kilometres and the area of its drainage basin 16,100 square kilometres. There are no settlements near the river. The nearest city is Batagay, and the nearest airfield Batagay Airport..
Grayling and lenok are found in the waters of the river.
