The Battle of Geronium or Gerunium took place during the Second Punic War, where a large skirmish and battle took place in the summer and autumn of 217 BCE respectively.

After winning the Battle of Ager Falernus, the army of Hannibal marched north then east towards Molise through Samnium. Hannibal was cautiously followed by the Roman army under the dictator Quintus Fabius Maximus Verrucosus, keeping with the Fabian strategy. This policy was becoming unpopular in Rome, and Fabius was compelled to return to Rome to defend his actions under the guise of observing religious obligations.

Marcus Minucius Rufus, who was left in command managed to catch the Carthaginians off guard near their camp in Geronium and inflict severe losses on them in a large skirmish, while 5,000 Romans were killed. This action caused the Romans, disgruntled with Fabius, to elevate Minucius to the equal rank of the dictator. Minucius took command of half the army and camped separately from Fabius near Geronium. Hannibal, informed of this development, laid an elaborate trap, which drew out Minucius and his army in detail, and then attacked it from all sides. The timely arrival of Fabius with the other half of the army enabled Minucius to escape, but with a substantial number of Romans killed. After the battle, Minucius turned over his army to Fabius and resumed the duties of Master of Horse.