Troilus and Criseyde is an epic poem by Geoffrey Chaucer which re-tells in Middle English the tragic story of the lovers Troilus and Criseyde set against a backdrop of war during the siege of Troy. It was written in rime royale and probably completed during the mid-1380s. Many Chaucer scholars regard it as the poet's finest work. As a finished long poem it is more self-contained than the better known but ultimately unfinished The Canterbury Tales. This poem is often considered the source of the phrase: "all good things must come to an end" (3.615).

Although Troilus is a character from Ancient Greek literature, the expanded story of him as a lover was of Medieval origin. The first known version is from Beno