The River Rhaeadr (Welsh: Afon Rhaeadr) is a river in Wales.
It starts at the Pistyll Rhaeadr waterfall a few miles from the village of Llanrhaeadr-ym-Mochnant, where the Afon Disgynfa falls over a 240-foot (73 m) cliff-face, after which the river is known as the Afon Rhaeadr.
Downstream, the Afon Rhaeadr runs into the Afon Tanat.