William de Ferrers, 5th Earl of Derby (1193 - March, 1254), was an English nobleman.

He was born in Derbyshire, England, the son of William de Ferrers, 4th Earl of Derby and Agnes of Chester, a daughter of Hugh of Kevelioc, Earl of Chester and Bertrada de Montfort. After doing homage to King Henry III, he had livery of Chartley Castle and other lands of his mother's inheritance. He accompanied King Henry to France in 1230. He sat in parliament in London in the same year.

William Ferrers married Sibyl Marshal, one of the daughters and co-heirs of William Marshal, 1st Earl of Pembroke. They had seven daughters.

In 1238, he married Margaret de Quincy (born 1218), daughter of Roger de Quincy, Earl of Winchester and Helen of Galloway. Bizarrely, Margaret was both the stepmother and stepdaughter of William's daughter, Eleanor.

He suffered from gout from youth, and always traveled in a litter. He was accidentally thrown from his litter while crossing a bridge, and died of the resulting injuries. William de Ferrers is buried at Merevere Abbey, Warwickshire, England. His widow died on March 12, 1280.