Frederick II ; 13 December 1272 – 25 June 1337) was the regent of the Kingdom of Sicily from 1291 until 1295 and subsequently King of Sicily from 1295 until his death. He was the third son of Peter III of Aragon and served in the War of the Sicilian Vespers on behalf of his father and brothers, Alfonso ΙΙΙ and James ΙΙ. He was confirmed as king by the Peace of Caltabellotta in 1302. His reign saw important constitutional reforms: the Constitutiones regales, Capitula alia, and Ordinationes generales.

The Kingdom of Sicily was a state that existed in Sicily and the south of the Italian Peninsula plus, for a time, in Northern Africa from its founding by Roger II of Sicily in 1130 until 1816. It was a successor state of the County of Sicily, which had been founded in 1071 during the Norman conquest of the southern peninsula. The island was divided into three regions: Val di Mazara, Val Demone and Val di Noto.