John III 'Red' Comyn, Lord of Badenoch and Lord of Lochaber, also known simply as the Red Comyn (died February10, 1306) is a Scottish nobleman who is an important figure in the Wars of Scottish Independence, and is Guardian of Scotland during the Second Interregnum 1296–1306.

He is best known for having been stabbed to death by the future Robert I of Scotland before the altar at the church of the Greyfriars at Dumfries.

His father, John II Comyn, Lord of Badenoch, known as the Black Comyn, was one of the Competitors for the Crown of Scotland, claiming his descent from King Donald III of Scotland.

His mother was Eleanor Balliol, eldest daughter of John I de Balliol, father of King John Balliol.

The Red Comyn might thus be said to have combined two lines of royal descent, Gaelic and Norman.

He has, moreover, links with the royal house of England: in the early 1290s he marries Joan de Valence, daughter of William de Valence, 1st Earl of Pembroke, an uncle of Edward I.