Poulanass Waterfall is a series of small cascades set within the oak woodlands of Glendalough, a glacial valley in County Wicklow, Ireland. Fed by the Poulanass stream, the falls spill down into plunge pools before draining toward the Upper Lake.

The name derives from the Irish "Poll an Eas," meaning "Hole of the Waterfall." The site sits within Wicklow Mountains National Park, close to Glendalough's celebrated 6th-century monastic ruins.

The waterfall is reached via a short but steep path that climbs alongside the cascades and plunge pools before crossing above the falls and descending through mixed woodland back to the valley floor.

The surrounding forest is noted for its moss-covered character, variety of woodland birds, and roaming wild goats. The trail is generally rated moderate in difficulty.