Frederick of Sicily may refer to:

• Frederick II, Holy Roman Emperor (1194-1250), also known as Frederick I of Sicily
• Frederick III of Sicily (1272–1337), self-styled the third despite being the second Frederick to rule Sicily (Trinacria)
• Frederick the Simple (1341–1377), third Frederick to rule Sicily (Trinacria)
• Frederick IV of Naples (1452–1504), continued Neapolitan claim to Kingdom of Sicily