| Afon Alun | |
| Subdivision Type1: | Country |
| Subdivision Name1: | United Kingdom, Wales |
| Subdivision Type3: | Region |
| Subdivision Name3: | South Wales |
| Subdivision Type4: | County |
| Subdivision Name4: | Vale of Glamorgan |
| Length Km: | 7.2 |
| Discharge2 Location: | Ewenny River |
| Source1 Location: | Llandow, Vale of Glamorgan, Wales |
| Mouth: | Ewenny River |
Afon Alun is a river in the Vale of Glamorgan, south Wales. It is a tributary of the Ewenny River, which it joins to the south of Bridgend.[1]
Two streams join near Llandow village to form the river: the Stembridge Brook and the Llandow Brook. After the confluence it flows in a broadly north-westerly direction following the route of the Vale of Glamorgan railway until it joins the Ewenny River just upstream of Ogmore Castle.
The river has one tributary, the Colwinston Brook, which, joins the river near the village of Colwinston.