Odd John: A Story Between Jest and Earnest is a 1935 science fiction novel by the British author Olaf Stapledon. The novel explores the theme of the Übermensch (superman) in the character of John Wainwright, whose supernormal human mentality inevitably leads to conflict with normal human society and to the destruction of the utopian colony founded by John and other superhumans.

The novel resonates with the ideas of Friedrich Nietzsche and the work of English writer J. D. Beresford, with an allusion to Beresford's superhuman child character of Victor Stott in The Hampdenshire Wonder (1911). As the devoted narrator remarks, John does not feel obliged to observe the restricted morality of Homo sapiens. Stapledon's recurrent vision of cosmic angst – that the universe may be indifferent to intelligence, no matter how spiritually refined – also gives the story added depth. Later explorations of the theme of the superhuman and of the incompatibility of the normal with the supernormal occur in the works of Stanisław Lem, Frank Herbert, Wilmar Shiras, Robert Heinlein and Vernor Vinge, among others.

The book is mentioned by Julian May in Intervention, part of the Galactic Milieu Series. It is also responsible for coining the term "homo superior".