Sant'Alessio Siculo (Sicilian: Sant'Alessiu Sìculu) is a comune (municipality) in the Metropolitan City of Messina in the Italian region Sicily, located about 180 km east of Palermo and about 35 km southwest of Messina. Its main attraction is a castle built in the 11th century by the Byzantine emperor Alexios I Comnenos in his war against the Normans and the Arabs, who also held it. It sits on the promontory Capo Sant'Alessio overlooking the sea and beach.