Robin Hood is an English folk hero of the Middle Ages. According to most legends, he lived and worked out of the Sherwood Forest in Nottinghamshire with his band of Merry Men. The Sheriff of Nottingham is traditionally his nemesis. Robin Hood is an archetypal outlaw figure, though he transformed over the centuries from a vicious rebel to a vigilante seeking justice and a champion of the poor. No historical Robin Hood has ever been identified, but even if one existed, the mythical version has certainly become an important entity in its own right.

The earliest recorded references to Robin Hood, or outlaws with a similar name, appear in legal records from the 13th century. The name seems to have been a generic term for an outlaw, and its origins are unknown. Literary sources from the medieval period suggest that Robin Hood was a popular subject in minstrel ballads and a sort of hero of the common folk, if a bane to law enforcement. Written stories and dramas specifically about Robin Hood did not appear until the 15th century, but the stories undoubtedly predated that era in the oral tradition.

In early stories, Robin Hood is cruel and self-interested and holds complete control over his followers. Nevertheless, he was still a hero and a trickster figure, and people often dressed as Robin Hood during May Day celebrations. It may be because of this tradition that Robin Hood's romantic interest is Maid Marian, a mythological figure associated with May Day, in many stories.

Beginning in the 16th century, Robin Hood tales make mention of his stealing from the rich and giving to the poor, and the figure became increasingly gentrified and conservative as the centuries wore on. Robin Hood became a knight, though earlier stories identify him as a yeoman, and Maid Marian became the object of his courtly love. Though he was still an outlaw, Robin Hood was also a moral figure, as he fought against the usurper of the throne, Prince John, and his crony, the Sheriff of Nottingham, while King Richard the Lionhearted was away fighting the Crusades. This detail places Robin Hood in the late 12th century, though earlier legends are not specific as to the time that he was active. The legend of Robin Hood also changed over the years to depict the band of Merry Men as an egalitarian group motivated by justice rather than self-interest.

Robin Hood's popularity as a subject for literature, theatre, and film continues to the present day. A BBC mini-series titled Robin Hood aired in Britain in late 2006 and began showing on BBC America on 3 March 2007. The University of Nottingham began offering a Master's degree in Robin Hood scholarship in 2007.