The Sugar Loaf is a prominent hill in Carmarthenshire, Wales, beside the A483 trunk road, some south-west of Llanwrtyd Wells. It is a popular viewpoint and picnic spot within easy reach on foot from the roadside car parks to the northeast and to the south. There is a stop on the nearby Heart of Wales Line called Sugar Loaf railway station.
The name Sugar Loaf has been applied to numerous hills which have a perceived resemblance to a sugarloaf; the nearest is the Sugar Loaf on the border between Powys and Monmouthshire.