The siege of Lilybaeum lasted for nine years, from 250 to 241 BCE, as the Roman army laid siege to the Carthaginian-held Sicilian city of Lilybaeum (modern Marsala) during the First Punic War. Rome and Carthage had been at war since 264 BCE, fighting mostly on the island of Sicily or in the waters around it, and the Romans were slowly pushing the Carthaginians back. By 250 BCE, the Carthaginians held only the cities of Lilybaeum and Drepana; these were well-fortified and situated on the west coast, where they could be supplied and reinforced by sea without the Romans being able to use their superior army to interfere.

In mid-250 BCE the Romans besieged Lilybaeum with more than 100,000 men but an attempt to storm Lilybaeum failed and the siege became a stalemate. The Romans then attempted to destroy the Carthaginian fleet but the Roman fleet was destroyed in the naval Battles of Drepana and Phintias; the Carthaginians continued to supply the city from the sea. Nine years later, in 242 BCE, the Romans built a new fleet and cut off Carthaginian shipments. The Carthaginians reconstituted their fleet and dispatched it to Sicily loaded with supplies. The Romans met it not far from Lilybaeum and at the Battle of the Aegates in 241 BCE the Romans defeated the Carthaginian fleet. The Carthaginians sued for peace and the war ended after 23 years with a Roman victory. The Carthaginians still held Lilybaeum but by the terms of the Treaty of Lutatius, Carthage had to withdraw its forces from Sicily and evacuated the city the same year.