Robin Hood: Prince of Thieves is a 1991 American action adventure film based on the English folk tale of Robin Hood and loosely set in the 12th century. Directed by Kevin Reynolds and written by Pen Densham and John Watson, the film stars Kevin Costner as Robin Hood, Morgan Freeman as Azeem, Christian Slater as Will Scarlett, Mary Elizabeth Mastrantonio as Marian, and Alan Rickman as the Sheriff of Nottingham.

The film received mixed reviews from critics. It was a box office success, grossing $390.5 million worldwide, making it the second-highest-grossing film of 1991. Rickman received the BAFTA Award for Best Actor in a Supporting Role for his performance as George, Sheriff of Nottingham. The theme song "(Everything I Do) I Do It for You" by Bryan Adams was nominated for the Academy Award for Best Original Song, and it won the Grammy Award for Best Song Written for Visual Media.

In 1194, English nobleman Robin of Locksley has spent years in an Ayyubid prison in Jerusalem, having followed King Richard the Lionheart on the Third Crusade. Robin and his comrade Peter Dubois escape, saving the life of a Moor named Azeem.

Mortally wounded, Peter makes Robin swear to protect his sister Marian, and Robin returns to England with Azeem, who vows to accompany him until his life debt is repaid. In King Richard's absence, the cruel Sheriff of Nottingham plots to seize the throne for himself and has Robin's father killed for remaining loyal to the king.

Arriving home four months later, Robin saves a young boy from the Sheriff's ruthless cousin, Guy of Gisbourne. He finds his father's corpse and his family's servant Duncan blinded by Gisbourne; Duncan explains that Robin's father was falsely accused of devil worship. The Sheriff consults the witch Mortianna, who foresees King Richard's return and that Robin and Azeem "will be our deaths".

Robin tells Marian of her brother's death, but she sees little need for his protection. Fleeing the Sheriff's forces into Sherwood Forest, Robin, Duncan and Azeem encounter a group of outlaws led by Little John, who challenges Robin to a duel. Robin wins and earns John's friendship, but the bandit Will Scarlet refuses to trust him. Confronting the corrupt Bishop of Hereford for his role in his father's death, Robin humiliates the Sheriff, who sends Gisbourne to terrorize the peasants in the search for "Robin of the Hood".

Despite the price on his head, Robin shapes the growing band of outlaws into a formidable force against the Sheriff. They rob rich folk passing through the forest and distribute the stolen wealth and food among the poor, and are joined by the beer-loving Friar Tuck.

Marian offers Robin any aid she can, and they fall in love. Robin's success and public support infuriate the Sheriff, who worsens his abuse of the peasants and kills Gisbourne for failing to stop the outlaws. Mortianna advises the Sheriff to recruit fearsome Celtic warriors from Scotland and that he must marry someone of royal blood: Marian, the king's cousin.