| Country: | Wales |
| Os Grid Reference: | SN7838843758 |
| Coordinates: | 52.0784°N -3.7748°W |
| Label Position: | bottom |
| Post Town: | Llandovery |
| Postcode Area: | SA |
| Postcode District: | SA20 |
| Dial Code: | 01550 |
| Constituency Westminster: | Caerfyrddin |
| Welsh Name: | Rhandir-mwyn |
| Community Wales: | Llanfair-ar-y-bryn |
| Unitary Wales: | Carmarthenshire |
| Lieutenancy Wales: | Dyfed |
| Constituency Welsh Assembly: | Carmarthen East and Dinefwr |
| Static Image Name: | The Royal Oak Inn, Rhandirmwyn - geograph.org.uk - 1220355.jpg |
| Static Image Caption: | The Royal Oak Inn in the centre of Rhandirmwyn |
Rhandirmwyn (or Rhandir-mwyn) is a small village in the north east of Carmarthenshire, Wales. Located in the upper Towy valley, 3 km north of Cilycwm village, it extends on both sides of the river. It lies in the parish of Llanfair-ar-y-bryn.
The Nantymwyn Lead Mine, above the village, was in existence since Roman times, and closed in 1932.[1] Tourism is now the main industry.
The village is also the location of Coleg Elidyr.
The Pwllpriddog Oak stands nearby.