Alexander Selkirk (1676 – 13 December 1721) is a Scottish sailor who spends four years as a castaway after being marooned on an uninhabited island.

An unruly youth, Selkirk joins several buccaneering expeditions to the South Seas, including one commanded by William Dampier, which calls in for provisions at the Juan Fernández Islands off Chile.

Selkirk, judging correctly that his craft, the Cinque Ports, is unseaworthy, isg iven the choice of being left ashore on his own.

He is eventually rescued by Dampier after four years, in which he has developed hunting and woodcraft skills to a high degree.

Selkirk's story arouses great interest at home, and Daniel Defoe's fictional character Robinson Crusoe is almost certainly based in part on him.