The War of Jenkins' Ear, or Guerra del Asiento, was a conflict lasting from 1739 to 1748 between Britain and the Spanish Empire. The majority of the fighting took place in New Granada and the Caribbean Sea, with major operations largely ended by 1742. It was related to the 1740 to 1748 War of the Austrian Succession. The name was coined in 1858 by British historian Thomas Carlyle, and refers to Robert Jenkins, captain of the British brig Rebecca, whose ear was allegedly severed by Spanish coast guards while searching his ship for contraband in April 1731.

Response to the incident was tepid until opposition politicians in Parliament, backed by the South Sea Company, used it seven years later to incite support for a war against Spain, hoping to improve British trading opportunities in the Caribbean. They also wanted to retain the lucrative Asiento de Negros giving British slave traders permission to sell slaves in Spanish America, which is why the Spanish call it the Guerra del Asiento. Unsuccessful British attacks in 1741 on the ports of Cartagena and Havana resulted in heavy casualties, primarily from disease, and were not repeated.

Apart from minor fighting in Florida and Georgia, after 1742 the conflict was largely subsumed into the War of the Austrian Succession, which involved most of the powers of Europe, and ended with the 1748 Treaty of Aix-la-Chapelle. The war is remembered in British naval history for Admiral George Anson's voyage around the world from 1740 to 1744.