John Galt (/ɡɔːlt/) is a character in Ayn Rand's novel Atlas Shrugged (1957). Although he is not identified by name until the last third of the novel, he is the object of its often-repeated question "Who is John Galt?" and of the quest to discover the answer. Also, in the later part it becomes clear that Galt had been present in the book's plot all along, playing several important roles though not identified by name.

As the plot unfolds, Galt is acknowledged to be a philosopher and inventor; he believes in the power and glory of the human mind, and the rights of individuals to use their minds solely for themselves. He serves as a highly individualistic counterpoint to the collectivist social and economic structure depicted in the novel, in which society is based on oppressive bureaucratic functionaries and a culture that embraces mediocrity in the name of egalitarianism, which the novel posits is the end result of collectivist philosophy.