Fleance (/ˈfleɪɒns/ FLAY-onss; also spelled Fléance or Fleans; Latin: Fleanchus) is a figure in legendary Scottish history. He was depicted by 16th-century historians as the son of Lord Banquo, Thane of Lochaber, and the ancestor of the kings of the House of Stuart. Fleance is best known as a character in William Shakespeare's play Macbeth, in which the Three Witches prophesy that Banquo's descendants shall be kings. Some screen adaptations of the story expand on Fleance's role by showing his return to the kingdom after Macbeth's death.

Shakespeare's play is adapted from Holinshed's Chronicles, a history of the British Isles written during the late 16th century. In Holinshed, Fleance escapes Macbeth and flees to England, where he fathers a son who later becomes the first hereditary steward to the King of Scotland.

In real life, 'Steward' eventually became the name 'Stewart' (later changed to a pseudo Frenchification 'Stuart'), and Walter Stewart married Princess Marjorie, daughter of Robert the Bruce. Their son, Robert II, began the Stewart/Stuart line of kings in Scotland. James VI and I, son of Mary, Queen of Scots, was the ninth Stewart/Stuart monarch (eighth king) of Scotland and the first of the Stuart monarchs of England and Ireland.

James VI & I was the reigning monarch when William Shakespeare wrote and produced Macbeth, which may have been in the new king's honour.

Fleance and his father Banquo are both fictional characters presented as historical fact by the Scottish historian Hector Boece, whose Scotorum Historiae (1526–27) was a source for Raphael Holinshed's Chronicles, a history of the British Isles popular in Shakespeare's time. In the Chronicles, Fleance – in fear of Macbeth – flees to Wales and marries Nesta, daughter of Gruffydd ap Llywelyn, the last native Prince of Wales. They have a son named Walter who makes his way back to Scotland and is appointed Royal Steward. According to legend, he fathered the Stuart monarchs of England and Scotland.

The Stuarts used their connection with Fleance and his marriage to the Welsh princess to claim a genealogical link with the legendary King Arthur. This, they hoped, would strengthen the legitimacy of their claim to the throne. In 1722, however, Richard Hay, a Scottish historian, presented strong evidence that not only was James not a descendant of Fleance, but also that neither Fleance nor Banquo ever even existed. Most modern scholars now agree that Fleance is not a real historical figure.

Max Förster suggested the name could be derived from the Gaelic Flannchad, lit. 'red warrior', or Flann-chú, "red hound." Boece's original Latin gives the name in ablative form as Fleancho, so suggesting a nominative form *Fleanchus.

Fleance appears in Shakespeare's Macbeth. However, only his childhood is portrayed; the rest of his story, as it is described in Holinshed's Chronicles, does not appear in Shakespeare's play. Scholars suggest that Shakespeare does not elaborate on Fleance's life after his escape from Scotland to avoid unnecessary distraction from the story of Macbeth himself. In the First Folio, his name is spelled "Fleans" nine times, while "Fleance" only appears four times, but the latter spelling has become standard.