The Second Punic War, which lasted from 218 to 201 BC, was the second of three wars fought between Carthage and Rome, the two main powers of the western Mediterranean in the 3rd century BC. For seventeen years, the two states struggled for supremacy, primarily in Italy and Iberia, but also on the islands of Sicily and Sardinia and, towards the end of the war, in North Africa. After immense material and human losses on both sides, the Carthaginians were defeated. Macedonia, Syracuse, and several Numidian kingdoms were drawn into the fighting; and Iberian and Gallic forces fought on both sides. There were three main military theatres during the war: Italy, where the Carthaginian general Hannibal repeatedly defeated the Roman legions, with occasional subsidiary campaigns in Sicily, Sardinia and Greece; Iberia, where Hasdrubal, a younger brother of Hannibal, defended the Carthaginian colonial cities with mixed success until moving into Italy; and Africa, where the war was decided. The war was the closest since Brennus's sack of Rome in 390 BC that the Roman state came to destruction, and it would not be threatened with destruction again until the 5th century.

In 219 BC Hannibal besieged, captured and sacked the pro-Roman city of Saguntum, prompting a Roman declaration of war on Carthage in spring 218 BC. That year, Hannibal surprised the Romans by marching his army overland from Iberia, through Gaul and over the Alps to Cisalpine Gaul (modern northern Italy). Reinforced by Gallic allies, he obtained crushing victories over the Romans at the battles of Trebia (218) and Lake Trasimene (217). Moving to southern Italy in 216, Hannibal defeated the Romans again at the Battle of Cannae, where he annihilated the largest army the Romans had ever assembled.

After the death or capture of more than 120,000 Roman troops in less than two years, many of Rome's Italian allies, notably Capua, defected to Carthage, giving Hannibal's allies control over much of southern Italy. As Syracuse and Macedonia joined the Carthaginian side after Cannae, the conflict spread. Between 215 and 210 BC the Carthaginians attempted to capture Roman-held Sicily and Sardinia, but were unsuccessful.

The Romans took drastic steps to raise new legions, enrolling slaves, criminals, and those who did not meet the usual property qualification and so vastly increasing the number of men they had under arms. For the next decade the war in southern Italy continued, with Roman armies slowly recapturing most of the interior in north-east Iberia and the Carthaginians repeatedly attempted and failed to reduce it.

In 211 BC the Romans took the offensive in Iberia and were decisively defeated, while maintaining their hold on the north east. In 209 BC the new Roman commander Publius Scipio captured Carthago Nova, the main Carthaginian base in the peninsula. In 208 BC Scipio defeated Hasdrubal, although Hasdrubal was able to move most of his troops into Gaul and then northern Italy in spring 207 BC. This new Carthaginian invasion was defeated at the Battle of the Metaurus.

At the Battle of Ilipa in 206 Scipio permanently ended the Carthaginian presence in Iberia. Scipio then invaded Carthaginian Africa in 204, compelling the Carthaginian Senate to recall Hannibal's army from Italy. The final engagement of the war took place between armies under Scipio and Hannibal at the Battle of Zama in 202 and resulted in Hannibal's defeat and in Carthage suing for peace.

The peace treaty imposed on the Carthaginians stripped them of all of their overseas territories, and some of their African ones. An indemnity of 10,000 silver talents was to be paid over 50 years. Carthage was prohibited from waging war outside Africa, and in Africa only with Rome's express permission. Many senior Carthaginians wanted to reject it, but Hannibal spoke strongly in its favour and it was accepted in spring 201 BC. Henceforth it was clear that Carthage was politically subordinate to Rome. Scipio was awarded a triumph and received the agnomen "Africanus". Due to the harsh terms of the peace treaty imposed on Carthage, the term "Carthaginian peace" has been coined in the 20th century to describe any peace treaty with terms designed to cripple the losing side of a war permanently.