Vathek (alternatively titled Vathek, an Arabian Tale or The History of the Caliph Vathek) is a Gothic novel written by William Thomas Beckford. It was composed in French in 1782, and then translated into English by Reverend Samuel Henley, in which form it was published in 1786.

Vathek capitalised on the 18th century obsession with all things Oriental (see Orientalism), which was inspired by Antoine Galland's translation of The Arabian Nights (itself re-translated, into English, in 1708). Beckford was also influenced by similar works from the French writer Voltaire. His originality lay in combining the popular Oriental elements with the Gothic stylings of Horace Walpole's The Castle of Otranto (1764). The result stands alongside Walpole's novel and Mary Shelley's Frankenstein (1818) in the first rank of early Gothic fiction.

The novel concerns the fall from power of the Caliph Vathek, who renounces Islam and engages with his ally Nouronihar in a series of licentious and deplorable activities designed to gain him supernatural powers. At the end of the novel, instead of attaining these powers, Vathek descends into a hell ruled by the demon Eblis where he is doomed to wander endlessly and speechlessly. Eblis, the architect of Vathek's damnation, was modelled on Iblis or Azazel; Beckford's use of the name is derived from John Milton's Paradise Lost (see Fallen angel).