The Great Hurricane of 1780, also known as Huracán San Calixto, the Great Hurricane of the Antilles, the Great Hurricane of the West Indies, and the 1780 Disaster, was the deadliest Atlantic hurricane on record. An estimated 22,000 people died throughout the Lesser Antilles when the storm passed through the islands from October 10 to October 16. Specifics on the hurricane's track and strength are unknown, as the official Atlantic hurricane database only goes back to 1851.The hurricane struck Barbados likely as a Category 5 hurricane, with at least one estimate of wind speeds as high as 200 mph (320 km/h) (greater than any in recorded Atlantic basin history) before moving past Martinique, Saint Lucia, and Sint Eustatius, and causing thousands of deaths on those islands. Coming in the midst of the American Revolution, the storm caused heavy losses to the British fleet contesting for control of the area, largely weakening British control over the Atlantic. The hurricane later passed near Puerto Rico and over the eastern portion of Hispaniola, causing heavy damage near the coastlines. It ultimately turned to the northeast and was last observed on October 20 southeast of Atlantic Canada.

The death toll from the Great Hurricane alone exceeds that of many entire decades of Atlantic hurricanes. Estimates are marginally higher than for Hurricane Mitch, the second-deadliest Atlantic storm, for which figures are likely more precise. The hurricane was part of the disastrous 1780 Atlantic hurricane season, with two other deadly storms occurring in October.