David Vaughan Icke (born 29 April 1952) is an English conspiracy theorist and author of more than 20 books, self-published since the mid-1990s. He is best known for claiming that inter-dimensional reptilian beings and their human hybrid bloodlines secretly control world events, which made him the most prominent popularizer of the modern reptilian theory. Jewish community organizations and researchers of antisemitism have long said his work recycles antisemitic conspiracy tropes, and Australia and the Netherlands have barred him from entering.

Born in Leicester, Icke was a youth goalkeeper with Coventry City and played for Hereford United before rheumatoid arthritis ended his career at 21. He became a journalist and, from 1981, a BBC sports presenter on programmes including Newsnight, Breakfast Time and Grandstand. He was also a national spokesman for the Green Party. The BBC ended his contract in 1990 after he said he would go to prison rather than pay the poll tax. In 1991, after visits to a psychic, he announced that he was a "son of the Godhead" and repeated predictions of coming disasters on the BBC's Wogan, where the studio audience's laughter made him a national figure of ridicule.

Over the next decade his books built a single cosmology. In The Biggest Secret (1999) he described a reptilian race, which he links to the Anunnaki of Mesopotamian myth, interbreeding with humans to produce a ruling "Babylonian Brotherhood." He later added ideas about a simulated reality broadcast from the Moon and Saturn. The religious-studies scholar David G. Robertson traces the reptilian theme to the ancient-astronaut writer Zecharia Sitchin and the Zulu healer Credo Mutwa.

Criticism has followed him throughout that work. His endorsement of The Protocols of the Elders of Zion, an antisemitic forgery, in books published in 1994 and 1995 led his publisher to drop him. The Community Security Trust, which monitors antisemitism in Britain, has described his "Rothschild Zionist" conspiracy as a new version of a very old antisemitic theory. Icke denies being antisemitic and says his reptilians are literal, not a code for Jews. Australia cancelled his visa in February 2019 on character grounds after a campaign by the Anti-Defamation Commission, and Icke called himself the victim of a smear campaign. In 2020 Facebook, YouTube and Twitter removed his accounts over COVID-19 misinformation, including false claims linking the virus to 5G networks. In November 2022 the Netherlands imposed a two-year entry ban, which also covered the Schengen Area, before a planned Amsterdam rally. A Dutch court upheld it in December 2024, finding that his theories contribute to the social acceptance of antisemitism.

His audience in UFO circles persisted in 2026. In March he gave a long interview to Chris Ramsay's Area52 podcast covering reptilian shape-shifting, an "astral" control system and underground bases. More than three decades after the Wogan interview, Icke remains the best-known source of the reptilian-elite theory, and the antisemitism findings and entry bans attached to that theory are a defining part of his public record.