The Siege of Rhegion occurred in 381 BC at the start of the Syracusan-Rhegian War. The Syracusan tyrant Dionysius I besieged and captured the rival Greek polis of Rhegion, establishing a foothold at the southern tip of Italy (in present-day Calabria).
Dionysius invaded mainland Italy at the head of three armies in the spring of 381 BC, crossing over from the Sicilian port of Messina and encamping on the Calabrian coast. He declared war on Rhegion once on Rhegian soil, and his armies crushed two Rhegian armies sent to repel his invasion at the Battle of Scilla. With this immediate threat dealt with, Dionysius sent his son Dionysius the Younger north to capture the port town of Locri (home of his wife Doris of Locri), while he and his general Hilarion marched their armies to besiege the city of Rhegion (Reggio Calabria) itself. The Syracusan armies stood little chance against the city's defensive walls and its large garrison, which was joined by the remnants of the Rhegian armies defeated at Scilla. However, Dionysius' admiral Dolops brought his fleet into Rhegion's harbor, enabling the Syracusans to launch an amphibious assault on the port in conjunction with a land assault. The Syracusans stormed the city with 1,493 losses, overwhelming the defenders. The populace of Rhegion quickly grew content with Dionysius' rule, as he incorporated them into a wealthy, fellow Hellenic realm which was poised to conquer the rest of Magna Graecia.