Lancelot du Lac is a 1974 French fantasy drama film written and directed by Robert Bresson. It retells the story of Lancelot and Guinevere's love as Camelot and the Round Table fall apart. It is based on Arthurian legend and medieval romances, especially the Lancelot-Grail cycle, and the works of Chrétien de Troyes.

Lancelot du Lac, also written as Launcelot and other variants, is a character in some versions of Arthurian legend where he is typically depicted as King Arthur's close companion and one of the greatest Knights of the Round Table. In the French-inspired Arthurian chivalric romance tradition, Lancelot is an orphaned son of King Ban of the lost kingdom of Benoic, raised in a fairy realm by the Lady of the Lake. A hero of many battles, quests and tournaments, and famed as a nearly unrivalled swordsman and jouster, Lancelot becomes the lord of the castle Joyous Gard and personal champion of Arthur's wife, Queen Guinevere, despite suffering from frequent and sometimes prolonged fits of madness. But when his adulterous affair with Guinevere is discovered, it causes a civil war that, once exploited by Mordred, brings an end to Arthur's kingdom.