The Battle of Panormus was fought in Sicily in 250 BC during the First Punic War between a Roman army led by Lucius Caecilius Metellus and a Carthaginian force led by Hasdrubal, son of Hanno. The Roman force of two Roman and two allied legions defending the city of Panormus defeated the much larger Carthaginian army of 30,000 men and between 60 and 142 war elephants.

The war had commenced in 264 BC with Carthage in control of much of Sicily, where most of the fighting took place. In 256–255 BC the Romans attempted to strike at the city of Carthage in North Africa, but suffered a heavy defeat by a Carthaginian army strong in cavalry and elephants. When the focus of the war returned to Sicily, the Romans captured the large and important city of Panormus in 254 BC. Thereafter they avoided battle for fear of the war elephants which the Carthaginians had shipped to Sicily. In late summer 250 BC Hasdrubal led out his army to devastate the crops of the cities of Rome's allies. The Romans withdrew to Panormus and Hasdrubal pressed on to the city walls.

Once he arrived in Panormus, Metellus turned to fight, countering the elephants with a hail of javelins from earthworks dug near the walls. Under this missile fire the elephants panicked and fled through the Carthaginian infantry. The Roman heavy infantry then charged the Carthaginian left flank, which broke, along with the rest of the Carthaginians. The elephants were captured and later slaughtered in the Circus Maximus. This was the last significant land battle of the war, which ended nine years later in a Roman victory.

The main source for almost every aspect of the First Punic War is the historian Polybius (c. 200 – c. 118 BC), a Greek sent to Rome in 167 BC as a hostage. His works include a lost manual on military tactics, but he is best known for his Histories, written after 146 BC, or about a century after the end of the war. Polybius's work is considered broadly objective and neutral between the Carthaginian and Roman points of view.

Carthaginian written records were destroyed with their capital, Carthage, in 146 BC and Polybius's account of the First Punic War is based on several lost Greek and Latin sources. Polybius was an analytical historian and when possible interviewed participants in the events he wrote about. Only part of the first book of the 40 comprising Histories deals with the First Punic War. The accuracy of Polybius's account has been much debated over the past 150 years, but the modern consensus is to accept it largely at face value, and the details of the battle in modern sources are almost entirely based on interpretations of Polybius's account. The modern historian Andrew Curry considers Polybius "fairly reliable"; while Dexter Hoyos describes him as "a remarkably well-informed, industrious, and insightful historian". Other, later, ancient histories of the war exist, but in fragmentary or summary form. Modern historians usually take into account the later histories of Diodorus Siculus and Dio Cassius, although the classicist Adrian Goldsworthy states "Polybius' account is usually to be preferred when it differs with any of our other accounts". Other sources include inscriptions, coins and archaeological evidence.

Most male Roman citizens were liable for military service, and would serve as infantry, with a better-off minority providing a cavalry component. Traditionally, when at war the Romans would raise two legions of Roman troops and two alae of allies, each of 4,200 infantry and 300 cavalry (900 cavalry for the ala). A small number of the infantry served as javelin-armed skirmishers. The others were equipped as heavy infantry, with body armour, a large shield, and short thrusting swords. They were divided into three ranks, of which the front rank also carried two javelins, while the second and third ranks had a thrusting spear instead. Both legionary sub-units and individual legionaries fought in relatively open order. It was the long-standing Roman procedure to elect two consuls each year to each lead an army. An army was usually formed by combining a Roman legion with a similarly sized and equipped legion provided by their Latin allies.

Carthaginian citizens only served in their army if there was a direct threat to the city of Carthage. In most circumstances Carthage recruited foreigners to make up its army. Many were from North Africa which provided several types of fighters including: close-order infantry equipped with large shields, helmets, short swords and long thrusting spears; javelin-armed light infantry skirmishers; close-order shock cavalry carrying spears; and light cavalry skirmishers who threw javelins from a distance and avoided close combat. Both Iberia and Gaul provided small numbers of experienced infantry; unarmoured troops who would charge ferociously, but had a reputation for breaking off if a combat was protracted. The close-order African infantry would fight in a tightly packed formation known as a phalanx. Slingers were frequently recruited from the Balearic Islands. Roman and Greek sources refer to these foreign fighters derogatively as "mercenaries", but the modern historian Adrian Goldsworthy describes to this as "a gross oversimplification". They served under a variety of arrangements; for example, some were the regular troops of allied cities or kingdoms seconded to Carthage as part of formal treaties. The Carthaginians also employed war elephants; North Africa had indigenous African forest elephants at the time.

The Roman Republic had been aggressively expanding in the southern Italian mainland for a century before the First Punic War. It had conquered peninsular Italy south of the River Arno by 272 BC. By this time Carthage, with its capital in what is now Tunisia, had come to dominate southern Spain, much of the coastal regions of North Africa, the Balearic Islands, Corsica, Sardinia, and the western half of Sicily in a military and commercial empire. In the 3rd century BC Carthage and Rome were the preeminent powers in the western Mediterranean. In 264 BC the two cities went to war over the city of Messana (modern Messina) in the north-eastern tip of Sicily.