The Battle of Meloria was fought near the islet of Meloria in the Ligurian Sea on 5 and 6 August 1284 between the fleets of the Republics of Genoa and Pisa as part of the Genoese-Pisan War. The victory of Genoa and the destruction of the Pisan fleet marked the decline of the Republic of Pisa.

The Republic of Pisa (Italian: Repubblica di Pisa) was an independent state centered on the Tuscan city of Pisa, which existed from the 11th to the 15th century. It rose to become an economic powerhouse, a commercial center whose merchants dominated Mediterranean and Italian trade for a century, before being surpassed and superseded by the Republic of Genoa.

The republic's participation in the Crusades secured valuable commercial positions for Pisan traders, thereafter the city grew in wealth and power. Pisa was a historical rival to Genoa at sea and to Florence and Lucca on land.The power of Pisa as a mighty maritime nation began to grow and reached its apex in the 11th century when it acquired traditional fame as one of the main historical Maritime Republics of Italy.