The County of Sicily is a Norman state comprising the islands of Sicily and Malta from 1071 until 1130.

The county begins to form during the Christian reconquest of Sicily (1061–91) from the Muslim Emirate, established by conquest in 965.

The county is thus a transitionary period in the history of Sicily.

After the Muslims had been defeated and either forced out or incorporated into the Norman military, a further period of transition takes place for the county and the Sicilians.The County of Sicily is created by Robert Guiscard in 1071 for his younger brother Roger Bosso.

Guiscard himself had received the title Duke of Sicily (dux Siciliae) in 1059 from Pope Nicholas II as encouragement to conquer it from the Muslims.

In 1061 the first permanent Norman conquest (Messina) was made and in 1071, after the fall of Palermo, the capital of the emirate and future capital of the county, Guiscard invests Roger with the title of count and gives him full jurisdiction in the island save for half the city of Palermo, Messina, and the Val Demone, which he retains for himself.

Roger is to hold the county, which comprises conquests yet to be made under Guiscard.

In February 1091, the conquest of Sicily is completed when Noto falls.

The conquest of Malta is begun later that year; it is completed in 1127 when the Arab administration of the island is expelled.Robert Guiscard leaves Roger in an ambiguous relationship with his successors of the Duchy of Apulia and Calabria.

During the reigns of Roger II of Sicily and William II of Apulia conflict breaks out between the two Norman principalities, first cousins through Roger and Robert respectively.

Through the mediation of Pope Calistus II and in return for aid against a rebellion led by Jordan of Ariano in 1121, the childless William cedes all his Sicilian territories to Roger and names him his heir.

When William dies in 1127, Roger inherits the mainland duchy; three years later he merges his holdings to form the Kingdom of Sicily with the approval of Pope Anacletus II.