Vancouver Island is an island in the northeastern Pacific Ocean and part of the Canadian province of British Columbia. The island is 456 km (283 mi) in length, 100 km (62 mi) in width at its widest point, and 32,100 km² (12,400 sq mi) in total area, while 31,285 km² (12,079 sq mi) are of land. The island is the largest by area and the most populous along the west coasts of the Americas.

The southern part of Vancouver Island and some of the nearby Gulf Islands are the only parts of British Columbia or Western Canada to lie south of the 49th parallel. The southeast part of the island has one of the warmest climates in Canada, and since the mid-1990s has been mild enough in a few areas to grow Mediterranean crops such as olives and lemons.

The population of Vancouver Island was 864,864 as of 2021. Nearly half of that population (~400,000) live in the metropolitan area of Greater Victoria on the southern tip of the island, which includes Victoria, the capital of British Columbia. Other notable cities and towns on Vancouver Island include Nanaimo, Campbell River, Courtenay, Port Alberni and Parksville, all on or near the east coast.

Indigenous peoples have inhabited Vancouver Island for thousands of years, long before the arrival of Spanish and British naval expeditions in the late 18th century. The Spanish and British conjointly named it Quadra's and Vancouver's Island in commemoration of the friendly negotiations held in 1792 between the Spanish commander of Fort San Miguel in Nootka Sound, Juan Francisco de la Bodega y Quadra, and British naval captain George Vancouver, during the Nootka Crisis. (Bodega y Quadra's name was eventually dropped.) It is one of several North American locations named after George Vancouver, who between 1791 and 1794 explored the Pacific Northwest.

Vancouver Island is the world's 43rd largest island, Canada's 11th largest island, and Canada's second most populous island after the Island of Montreal.