Castaway 2000 is a reality TV programme broadcast on BBC One throughout 2000. The programme followed a group of thirty-six men, women, and children who were tasked with building a community on the Scottish island of Taransay, 1+7⁄8 miles (3 kilometres) off the west coast of Harris, Outer Hebrides.

Described as a pioneering early form of the new genre of reality TV, while a ratings success it nonetheless featured a number of issues during filming, leading to bad publicity and even a legal dispute. It launched the television career of participant Ben Fogle but, according to the Radio Times, the show is probably "remembered for little else."

Seven years later the BBC resurrected the show for Castaway 2007. In 2016 Channel 4 began airing a similar show, Eden, which drew many comparisons to and lessons from Castaway.