Space Cadet is a 1948 science fiction novel by Robert A. Heinlein about Matt Dodson, who joins the Interplanetary Patrol to help preserve peace in the Solar System. The story translates the standard military academy story into outer space: a boy from Iowa goes to officer school, sees action and adventure, shoulders responsibilities far beyond his experience, and becomes a man. It was published as the second of the series of Heinlein juveniles and inspired the media franchise around the character Tom Corbett, including the 1950s television series Tom Corbett, Space Cadet and radio show which made "Space Cadet" a household phrase whose meaning later shifted in popular culture.

Robert Anson Heinlein was an American science fiction author, aeronautical engineer, and naval officer. Sometimes called the "dean of science fiction writers", he was among the first to emphasize scientific accuracy in his fiction, and was thus a pioneer of the subgenre of hard science fiction. His published works, both fiction and non-fiction, express admiration for competence and emphasize the value of critical thinking. His plots often posed provocative situations which challenged conventional social mores. His work continues to have an influence on the science-fiction genre, and on modern culture more generally.