William de Forz, 3rd Earl of Albermarle (d. March 26, 1242) was an English nobleman.

He was the son of William de Forz (d. 1195), and Hawisa, 2nd Countess of Albermarle , a daughter of William le Gros, 1st Earl of Albermarle . His father was a minor noble from the village of Fors in Poitou; the toponymic is variously rendered as de Fors, de Forz, or de Fortibus.

The Earldom of Albermarle which de Forz inherited from his mother included a large estate in Yorkshire, notably the wapentake of Holderness and the castle of Skipsea , and the honor of Craven, as well as property in Lincolnshire and elsewhere. It had also included the county of Aumale, but this had recently been lost to the French, along with the rest of Normandy. De Forz was the first earl of Albermarle to see his earldom as wholly English.

He was generally loyal to King John during the baronial revolt against the king, though he did eventually join the barons after the people of London joined them and the king's cause looked hopeless. He was one of the 25 executors of the Magna Carta, but amongst them was probably the least hostile to the king.

The barons made de Forz constable of Scarborough Castle , but when soon after fighting began between the barons and the king, he went over to John's side, the only one of the 25 Magna Carta executors to do so. He fought for the king until the French capture of Winchester in June 1216, when again the king's cause looked hopeless. He then stayed on the barons side until their cause fell apart.

After John's death, he supported the new king Henry III, fighting in the siege of Montsorrel and at the Battle of Lincoln . But de Forz was one of the most recalcitrant supporters of old traditions of baronial independence, and he came into conflict with Hubert de Burgh, who was effectively regent, and later with the king himself. He eventually gave in when this cause was lost in 1224, and was thenceforth loyal to Henry III.

He married Avelina, daughter of Richard de Montfichet, and was succeeded by his son William de Forz, 4th Earl of Albermarle .