Grýla, is in Icelandic mythology, a horrifying monster and a giantess living in the mountains of Iceland. She is said to come from the mountains at Christmas in search of naughty children.

The Grýla legend has been frightening to the people of Iceland for many centuries - her name is even mentioned in Snorri Sturluson's thirteenth century Edda. Most of the stories told about Gryla were to frighten children – her favourite dish was a stew of naughty kids and she had an insatiable appetite. Grýla was not directly linked to Christmas until in the 17th century. By that time she had become the mother of the Yule Lads. A public decree was issued in 1746 prohibiting the use of Grýla and the Yule Lads to terrify children.

According to folklore Grýla has been married three times. Her third husband Leppalúði is said to be living with her in their cave in the Dimmuborgir lava fields, with the big black Yule Cat and their sons. As Christmas approaches, Grýla sets off looking for naughty boys and girls. The Grýla legend has appeared in many stories, poems, songs and plays in Iceland and sometimes Grýla dies in the end of the story.