Llangenny is a small hamlet in the Brecon Beacons National Park in southern Powys, Wales.
Llangenny has approximately 100 inhabitants and is a village in the Vale of Grwyney, the lower reaches of the Grwyne Fawr, which comprises Llangenny, Glangrwyney and Llanbedr.
The two main features of Llangenny are the parish church of St.Cenau or Saint Keyne and the public house, the Dragons Head Inn.
The area is popular with hill-walkers and for camping and outdoor activities.