Earl of Leicester is a title that has been created seven times. The first title was granted during the 12th century in the Peerage of England. The current title is in the Peerage of the United Kingdom and was created in 1837.

Simon de Montfort, 5th Earl of Leicester, known as Simon IV de Montfort and as Simon de Montfort the Elder, was a French nobleman and knight of the early 13th century. He is widely regarded as one of the great military commanders of the Middle Ages. He took part in the Fourth Crusade and was one of the prominent figures of the Albigensian Crusade. Montfort is mostly noted for his campaigns in the latter, notably for his triumph at Muret. He died at the Siege of Toulouse in 1218. He was Seigneur of Montfort from 1188 to his death and Earl of Leicester in England from 1204. He was also Viscount of Albi, Béziers and Carcassonne from 1213, as well as Count of Toulouse from 1215.