The Great Dividing Range, also known as the East Australian Cordillera or the Eastern Highlands, is a cordillera system in eastern Australia consisting of an expansive collection of mountain ranges, plateaus and rolling hills, that runs roughly parallel to the east coast of Australia and forms the fifth-longest land-based mountain chain in the world, and the longest entirely within a single country. It is mainland Australia's most substantial topographic feature and serves as the definitive watershed for the river systems in eastern Australia, hence the name.

The Great Dividing Range stretches more than 3,500 kilometres (2,175 mi) from Dauan Island in the Torres Strait off the northern tip of Cape York Peninsula, running the entire length of the eastern coastline through Queensland and New South Wales, then turning west across Victoria before finally fading into the Wimmera plains as rolling hills west of the Grampians region. The width of the Range varies from about 160 km (100 mi) to over 300 km (190 mi). The Greater Blue Mountains Area, Gondwana Rainforests and Wet Tropics of Queensland World Heritage Areas are located in the Range. The highest place in Australia, the 2,228 m (7,310 ft) Mount Kosciuszko, resides in the Snowy Mountains portion of southern Great Dividing Range.