A Knight's Tale is a 2001 American medieval action comedy film written, co-produced and directed by Brian Helgeland. The film stars Heath Ledger as William Thatcher, a peasant squire who poses as a knight and competes in tournaments, winning accolades and acquiring friendships with such historical figures as Edward the Black Prince (James Purefoy) and Geoffrey Chaucer (Paul Bettany). Its 14th-century story is intentionally anachronistic, with many modern pop culture references and a soundtrack featuring 1970s music. The film takes its name from Chaucer's "The Knight's Tale", part of The Canterbury Tales, and also draws several plot points from Chaucer's work.

A Knight's Tale was released by Columbia Pictures in the United States on May 11, 2001. It received mixed reviews from critics and grossed $117.5 million against a budget of $65 million.

In 2012, it was reported that a TV series adaptation was in development by American Broadcasting Company, written by Ronald D. Moore.