Llandissilio is a village and parish in the community of Llandissilio West in east Pembrokeshire, Wales on the A478 road between Efailwen to the north and Clunderwen to the south. A largely ribbon development along the main road, the village is surrounded by farmland.

The A478 road is a major road in Wales. The route is from its junction with the A487 at Cardigan, Ceredigion, to Tenby, Pembrokeshire. It crosses the Preseli Hills and winds through farmland for almost all of its route. The road just touches the very west of Carmarthenshire.