The Battle of the Bagradas River, also known as the Battle of Tunis, was a victory by a Carthaginian army led by Xanthippus over a Roman army led by Marcus Atilius Regulus in the spring of 255 BC, nine years into the First Punic War. The previous year, the newly constructed Roman navy established naval superiority over Carthage. The Romans used this advantage to invade Carthage's homeland, which roughly aligned with modern-day Tunisia in North Africa. After landing on the Cape Bon Peninsula and conducting a successful campaign, the fleet returned to Sicily, leaving Regulus with 15,500 men to hold the lodgement in Africa over the winter.

The military of Carthage was one of the largest military forces in the ancient world. Although Carthage's navy was always its main military force, the army acquired a key role in the spread of Carthaginian power over the native peoples of northern Africa and southern Iberian Peninsula from the 6th century BC and the 3rd century BC. Carthage's military also allowed it to expand into Sardinia and the Balearic Islands. This expansion transformed the military from a body of citizen-soldiers into a multinational force composed of a combination of allies, citizens and foreign mercenary units.