William, 5th Earl of Ross

William, 5th Earl of Ross (died 1372), was the son of Earl Hugh and Matilda Bruce, Robert the Bruce's sister, and first cousin of David II. His father fell at Halidon Hill in 1333; William returned from Norway in 1336 to take up the earldom.

In 1339 he forced the English garrison out of Perth by draining its moat. In 1346 he killed his vassal Ronald MacRuari at Elcho Priory and withdrew before Neville's Cross.

He joined the Highland lords' revolt of 1366 and died in 1372. He left the earldom to his daughter Euphemia.