A desert island or uninhabited island is an island that has yet to be (or is not currently) populated by humans. Uninhabited islands are often used in movies or stories about shipwrecked people, and are also used as stereotypes for the idea of "paradise". Some uninhabited islands are protected as nature reserves and some are privately owned. Devon Island in Canada is claimed to be the largest uninhabited island in the world.

Small coral atolls or islands usually have no source of fresh water, but at times a fresh water lens (Ghyben-Herzberg lens) can be reached with a well.

In the phrase "desert island," the adjective "desert" connotes a "desolate and sparsely occupied or unoccupied" area and does not imply that the island was previously inhabited and later deserted. The term "desert island" therefore typically refers to an undiscovered island. Note that a desert island does not have to be a desert.

The first known novels to be set on a desert island were Philosophus Autodidactus written by Ibn Tufail (1105–1185), followed by Theologus Autodidactus written by Ibn al-Nafis (1213–1288). The protagonists in both (Hayy in Philosophus Autodidactus and Kamil in Theologus Autodidactus) are feral children living in seclusion on a deserted island, until they eventually come in contact with castaways from the outside world who are stranded on the island. The story of Theologus Autodidactus, however, extends beyond the deserted island setting when the castaways take Kamil back to civilization with them.

Raymond Paul "Ray" Mears (born 7 February 1964) is an English woodsman, instructor, author and TV presenter. His TV appearances cover bushcraft and survival techniques, and he is best known for the TV series Ray Mears' Bushcraft, Ray Mears' World of Survival, Extreme Survival, Survival with Ray Mears, Wild Britain with Ray Mears and Ray Mears Goes Walkabout.

Mears grew up in Kenley, Greater London, and the North Downs, where he discovered a countryside abundant with wildlife. Educated at Reigate Grammar School, a co-educational independent school in Reigate, Surrey, he learned to track foxes in the forest at a young age. As a boy, he desired to sleep out on the trail, but unable to afford camping equipment, he resorted to setting up camp using what he could find in his surroundings.

Mears's enthusiasm for his subject, combined with his broad knowledge of survival and the uses which may be made of plants, trees and other natural materials found in woodland, forest or desert, have made him a popular figure in TV broadcasting in the UK.^{[citation needed]} He has travelled extensively across the world for his TV series and has learned survival techniques from the indigenous peoples he has met. In his programmes he demonstrates his knowledge of the wild, how to find food from seeds, berries, roots and other growing things, and how to survive by constructing temporary shelters, fires and canoes from natural materials.