The Treur River (from Afrikaans: mourning river) is a small river in the Drakensberg escarpment region of eastern Mpumalanga province, South Africa. The R532 motor route intersects it twice. Its ultimate origin is inside the Blyde River Canyon Nature Reserve, though most of its course is to the west of this protected area. It is a tributary of the Blyde River, and has no major tributaries of its own. There are two sharp drops in its course, at Poe Falls and Bourke's Luck Potholes respectively.
Treur means "mourning" in Dutch, and was thus named during a voortrekker expedition. In 1844, while still under the misapprehension that Hendrik Potgieter and his party had perished on their journey to Delagoa Bay, their distraught relatives named the river near their encampment, Treurrivier, or 'mourning river'.