The Fair Folk are a race of supernatural beings in The Chronicles of Prydain, a series of children's fantasy novels by Lloyd Alexander. The term "Fair Folk" is one of several titles often given to fairies, elves and similar human-like supernatural races in folklore. Alexander's Fair Folk most closely resemble dwarves or diminutive elves in appearance. Some of the Fair Folk appear in more beautiful forms.
In the novels, the Fair Folk live underground. They have outposts throughout Prydain and mines where they get supplies of beautiful gems, from which they take only the best, most flawless examples. The entrance to the subterranean Fair Folk kingdom is hidden under the Black Lake.
The Fair Folk are ruled by King Eiddileg, a hot-tempered and easily excitable little man. He harbors a great dislike and distrust for humans since his coronation as king. In The Book of Three, the companions enter the realm of the Fair Folk and come face to face with the King. He withholds from them the oracular pig Hen Wen.
Other significant Fair Folk include the dwarf Doli, a companion of the series' protagonist Taran, and Gwystyl, a depressed and melancholy fae who provides the heroes with information and aid (often unwillingly or after threat of "squeezing").
The Fair Folk are portrayed as ambivalent towards humans, though usually not antagonistic. They generally keep to themselves and have disdain for the foolish and awkward "mortals" who live above. However, they have less love for the Death-Lord Arawn and his minions and occasionally aid the forces of Prydain against him. It was mentioned by Doli in Taran Wanderer that the Fair Folk always honored the House of Lyr (Eilonwy's house). They also are honorbound to repay any debts they have to mortals. Usually this comes in the form of granting wishes or bestowing magical treasures.
At the conclusion of the series, following the downfall of Arawn, the Fair Folk retreat into their underground world (seemingly for good) when beings of magic depart from Prydain and a new age begins. This diminishing of magic resembles similar events in J.R.R. Tolkien's The Lord of the Rings and other works of fantasy.
The Fair Folk appear in the Disney animated film The Black Cauldron, loosely adapted from the first two novels of the Chronicles of Prydain. Unlike Alexander's dwarf-like description, the Disney Fair Folk more closely resemble the contemporary Victorian version of fairies and are depicted as tiny winged beings.