William Malet (fl. born before 1175–1215), feudal baron of Curry Mallet in Somerset, was one of the guarantors of Magna Carta. He served as Sheriff of Somerset and Dorset in 1209. The precise nature of his relationship to an earlier William Malet is unknown.
Amongst the manors comprising his feudal barony were his caput of Curry Mallet, where stood his castle, and Shepton Mallet in Somerset.
He married twice but left no male progeny, only three daughters and co-heiresses, who divided their father's estate.
By his first wife, whose name is unknown, Malet had a daughter.
By his second wife, Alice Basset, who was a daughter of Thomas Basset, Sheriff of Oxfordshire and Berkshire, William Malet had a daughter: