Percival or Perceval is one of King Arthur's legendary Knights of the Round Table. In Welsh his name is Peredur and his sister is known as Dindrane. While some scholars once believed that Percival, along with the legend of the Holy Grail, was of Persian origin, those theories have been rejected by the weight of scholarly opinion.

There are many versions of Percival's birth. In most accounts he is of noble birth; his father is either Sir Gawain or King Pellinore. His mother, usually unnamed, is sometimes recorded as Lady Ragnell .

Percival is often portrayed as an innocent who grew up uninitiated in the ways of men in the Welsh forests until he was 15. One version of the legend depicts Percival as a thief whom Lancelot took under his wing. After showing the virtues of a knight, Percival was knighted and invited to join the Knights of the Round Table.

Percival went to become one of the "greats" in Arthurian legend when he was one of only two (or three, depending on the source) knights to find the Holy Grail (the other being Sir Galahad). He is also credited with killing the Red Knight. In original versions of the story Percival is the only knight who achieved the Grail quest; subsequently his stature is matched (or usurped) by Sir Galahad.

Percival later married Lady Blanchefleur and become the King of Cartomek after healing the Fisher King. The story recurs as a potent metaphor in some modern retellings, particularly in T.S. Eliot's epic poem The Waste Land and the film The Fisher King.

Chrétien de Troyes wrote the first literary retelling of the Percival story, as Le Roman de Perceval ou le Conte du Graal . Wolfram von Eschenbach's Parzival and Sir Thomas Malory's Le Morte d'Arthur are two other famous accounts of his adventures. He eventually became the subject of Richard Wagner's opera Parsifal.