The River Gwaun (Welsh: Afon Gwaun, "Gwaun" meaning 'marsh, moor') is a river in Pembrokeshire, West Wales, which flows west to the sea at Fishguard (Welsh: Abergwaun - 'mouth of the Gwaun').
It has a total length of 9 miles (14 km) and is navigable by canoe for the lower third of its length, beginning west of Pontfaen.[1] Before Pontfaen, the river is joined by the Afon Cwmau which flows from the south.
The river (as Gwyne) appears on a 1578 parish map of Pembrokeshire.[2]