The Fourth Ottoman–Venetian War, also known as the War of Cyprus (Italian: Guerra di Cipro) is fought in 1570–1573 between the Ottoman Empire and the Republic of Venice, the latter joined by the Holy League, a coalition of Christian states formed under the auspices of the Pope and including Spain (with Naples and Sicily), the Republic of Genoa, the Duchy of Savoy, the Knights Hospitaller, the Grand Duchy of Tuscany and other Italian states.The war, the main event of Sultan Selim II's reign, begins when the Ottomans invade the Venetian-held island of Cyprus.

The capital Nicosia and several other towns fall quickly to the greatly superior Ottoman army, leaving only Famagusta in Venetian hands.

Christian reinforcements are delayed, and Famagusta eventually falls in August 1571 after a siege of eleven months.

Two months later, at the Battle of Lepanto, the united Christian fleet destroys the Ottoman fleet, but is unable to take advantage of this victory.

The Ottomans quickly rebuild their naval forces, and Venice is forced to negotiate a separate peace, ceding Cyprus to the Ottomans and paying a tribute of 300,000 ducats.