The Cretan War was a conflict between the Republic of Venice and her allies (chief among them the Knights of Malta, the Papal States and France) against the Ottoman Empire and the Barbary States, because it was largely fought over the island of Crete, Venice's largest and richest overseas possession. The war lasted from 1645 to 1669 and was fought in Crete, especially in the city of Candia, and in numerous naval engagements and raids around the Aegean Sea, with Dalmatia providing a secondary theater of operations.

Although most of Crete was conquered by the Ottomans in the first few years of the war, the fortress of Candia (modern Heraklion), the capital of Crete, resisted successfully. Its prolonged siege forced both sides to focus their attention on the supply of their respective forces on the island. For the Venetians in particular, their only hope for victory over the larger Ottoman army in Crete lay in successfully starving it of supplies and reinforcements. Hence the war turned into a series of naval encounters between the two navies and their allies. Venice was aided by various Western European nations, who, exhorted by the Pope and in a revival of crusading spirit, sent men, ships and supplies "to defend Christendom". Throughout the war, Venice maintained overall naval superiority, winning most naval engagements, but the efforts to blockade the Dardanelles were only partially successful, and the Republic never had enough ships to fully cut off the flow of supplies and reinforcements to Crete. The Ottomans were hampered in their efforts by domestic turmoil, as well as by the diversion of their forces north towards Transylvania and the Habsburg monarchy.

The prolonged conflict exhausted the economy of the Republic, which relied on the lucrative trade with the Ottoman Empire. By the 1660s, despite increased aid from other Christian nations, war-weariness had set in. The Ottomans on the other hand, having managed to sustain their forces on Crete and reinvigorated under the capable leadership of the Köprülü family, sent a final great expedition in 1666 under the direct supervision of the Grand Vizier. This began the final and bloodiest stage of the Siege of Candia, which lasted for more than two years. It ended with the negotiated surrender of the fortress, sealing the fate of the island and ending the war in an Ottoman victory. In the final peace treaty, Venice retained a few isolated island fortresses off Crete, and made some territorial gains in Dalmatia. The Venetian desire for a revanche would lead, barely 15 years later, to a renewed war, from which Venice would emerge victorious. Crete, however, would remain under Ottoman control until 1897, when it became an autonomous state; it was finally united with Greece in 1913.