The Tuntang (Indonesian: Kali Tuntang) is a major river of northern Central Java, Indonesia, about 400 km east of the capital Jakarta.

[1] It connects Lake Rawa Pening to the Java Sea, east of Semarang.

[2] There is a hydroelectric power station on the river near the lake.

The river flows in the central area of Java with a predominantly tropical monsoon climate (designated as Am in the Köppen-Geiger climate classification).

The warmest month is September when the average temperature is around 24 °C, and the coldest is June, at 20 °C.