Myrddin is Myrddin Wyllt, a figure in medieval Welsh legend.

Myrddin may also refer to:

Myrddin (Stargate), a character in the Stargate fictional universe Myrddin Emrys, or Merlin, a legendary figure in Arthurian legend Myrddin Fardd (1836–1921), Welsh writer Myrddin ap Dafydd (born 1956), Welsh writer and publisher

See also Clas Myrddin, or Merlin's Enclosure, an early name for Great Britain