Hicetas of Syracuse was a Pythagorean philosopher active in the 4th century BCE in Sicily. He belonged to the later Pythagorean tradition within the Greek communities of southern Italy and Sicily. No details of his personal life, education, or any authored texts survive. His ideas are known only through reports by later ancient writers.

His historical significance rests primarily on a single cosmological theory attributed to him. According to the Roman philosopher Cicero, Hicetas proposed that the Earth rotates daily on its own axis from west to east, while the celestial sphere of the fixed stars remains motionless. This same concept is also credited by ancient sources to other Pythagoreans, such as Ecphantus of Syracuse and Philolaus of Croton.

Hicetas’s theory represents an early challenge to the more prevalent ancient view of a completely stationary Earth. Modern scholars regard him as part of a minor but significant strand of pre-modern astronomical thought that considered terrestrial motion, long before the Copernican revolution. His existence also illustrates the geographical spread and enduring activity of Pythagorean philosophy in the western Greek world during the Classical period.