Garnedd Ugain, also known as Crib-y-Ddysgl, is a pyramidal mountain in Wales that forms part of the Snowdon Massif.

It is the second-highest peak in Wales, (Although with a far greater topographical prominence Carnedd Llywelyn is usually considered second highest).

It is also linked to Cwm Glas to the northeast via a steep arete called Clogwyn y Person, which joins the main Crib y Ddysgl ridge about 500 metres (1,600 feet) east of the summit.

Crib-y-Ddysgl (meaning "ridge of the dish" in Welsh) is the name used by Alan Dawson for the peak's listing as a Hewitt.

Carnedd Ugain in Welsh means "Cairn of the Twenty" (the form Garnedd is the result of soft mutation).