The Tonalli River, a perennial river that is part of the Hawkesbury-Nepean catchment, is located in the Blue Mountains region of New South Wales, Australia.

The Tonalli River rises on the eastern alopes of Mount Marrup within the Tonalli Range in remote country within the Greater Blue Mountains Area World Heritage Site, and flows generally east southeast, east northeast, and then east southeast, before reaching its confluence with the Wollondilly River within Lake Burragorang in Yerranderie State Conservation Area. The river descends 559 metres (1,834 ft) over its 26-kilometre (16 mi) course.

The river flows through parts of the Nattai and Kanangra-Boyd national parks and is a source of water for the Sydney region.

• List of rivers of New South Wales (L–Z)
• List of rivers of Australia
• Rivers of New South Wales

• "Lake Burragorang subcatchment". Hawkesbury Nepean River Health Strategy. Hawkesbury Nepean Catchment Management Authority. 2008.

34°08′S 150°21′E / 34.133°S 150.350°E / -34.133; 150.350