Garnedd Ugain, also known as Crib y Ddysgl, is a mountain in Wales that forms part of the Snowdon Horseshoe. It is the second highest peak in Wales, and lies just over one kilometre north of Snowdon itself.
Both Garnedd Ugain and Crib y Ddysgl appear on the Ordnance Survey's maps of the area. The name Crib Y Ddysgl refers to the east ridge whilst the summit is Garnedd or Carnedd Ugain.
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 Twenty" (the form Garnedd is the result of soft mutation). This was named after the Roman legion based in Caernarfon.