Sgwd Gwladys, also known as Lady Falls, is a waterfall on the Afon Pyrddin near the village of Pontneddfechan in the Brecon Beacons National Park, Wales.

The river plunges roughly 7–10 metres over a resistant band of gritstone known as the Twelve Foot Sandstone into a plunge pool surrounded by woodland.

The falls are best experienced in spring or after significant rainfall, when the flow is at its most powerful.

The waterfall is one of the most accessible in the area, reached via the fairly level Elidir Trail — a roughly 30-minute walk from Pontneddfechan along the riverside.

A notable feature above the falls is a former logan stone, a naturally balanced rocking block of gritstone that was displaced during Victorian times. Ruins near the site are believed to be those of an old corn mill.

Sgwd Gwladys also forms part of a broader waterfall trail that continues along the Afon Nedd Fechan to several further cascades.