Don Quixote (/ˌdɒn kiːˈhoʊtiː/; Spanish: [ˈdoŋ kiˈxote] ( listen)), fully titled The Ingenious Gentleman Don Quixote of La Mancha(Spanish: El ingenioso hidalgo don Quijote de la Mancha), is a Spanish novel by Miguel de Cervantes Saavedra. It follows the adventures of Alonso Quixano, an hidalgo who reads so many chivalric novels that he decides to set out to revive chivalry, under the name Don Quixote. He recruits a simple farmer, Sancho Panza, as his squire, who often employs a unique, earthly wit in dealing with Don Quixote's rhetorical orations on antiquated knighthood. Don Quixote is met by the world as it is, initiating such themes asintertextuality, realism, metatheatre, and literary representation.

Published in two volumes, in 1605 and 1615, Don Quixote is considered the most influential work of literature from the Spanish Golden Age and the entire Spanish literary canon. As a founding work of modern Western literature, and one of the earliest canonical novels, it regularly appears high on lists of the greatest works of fiction ever published. It has had major influence on the literary community, as evidenced by direct references in Alexandre Dumas' The Three Musketeers (1844) and Mark Twain's Adventures of Huckleberry Finn (1884). In a 2002 list, Don Quixote was cited as the "best literary work ever written".

Alonso Quixano, the protagonist of the novel, is a retired country gentleman nearing fifty years of age, living in an unnamed section of La Mancha with his niece and housekeeper. While mostly a rational man of sound reason, his reading of books of chivalry in excess has had a profound effect on him, leading to the distortion of his perception and the wavering of his mental faculties. In essence, he believes every word of these books of chivalry to be true though, for the most part, the content of these books is clearly fiction. Otherwise, his wits are intact.

He decides to sally forth as a knight-errant in search of adventure. He dons an old suit of armour, renames himself "Don Quixote," and names his skinny horse "Rocinante". He designates Aldonza Lorenzo, a neighboring farm girl, as his lady love, renaming her Dulcinea del Toboso, while she knows nothing of this.

He sets out in the early morning and ends up at an inn, which he believes to be a castle. He asks the innkeeper, whom he thinks to be the lord of the castle, to dub him a knight. He spends the night holding vigil over his armor, where he becomes involved in a fight with muleteers who try to remove his armor from the horse trough so that they can water their mules. The innkeeper then dubs him a knight to be rid of him, and sends him on his way.

Don Quixote next "frees" a young boy who is tied to a tree and beaten by his master and makes his master swear on the chivalric code to treat the boy fairly. The boy's beating is continued as soon as Quixote leaves. Don Quixote has a run-in with traders from Toledo, who "insult" the imaginary Dulcinea. He attacks them, only to be severely beaten and left on the side of the road. Don Quixote is found and returned to his home by a neighboring peasant.