George Psalmanazar (c. 1679 – 3 May 1763) was a Frenchman who claimed to be the first native of Formosa (today Taiwan) to visit Europe. For some years, he convinced many in Britain, but he was eventually revealed to be of European origin. He subsequently became a theological essayist, and a friend and acquaintance of Samuel Johnson and other noted figures in 18th-century literary London.

Although Psalmanazar intentionally obscured many details of his early life, it is believed that he was born in southern France, perhaps in Languedoc or Provence, some time between 1679 and 1684. His birth name is unknown. According to his posthumously published autobiography, he was educated in a Franciscan school and then a Jesuit academy. In both these institutions he claimed to have been celebrated by his teachers for what he called "my uncommon genius for languages". He claims that he attained fluency in Latin by the age of seven or eight, and excelled in competition with children twice his age. Later encounters with a sophistic philosophy tutor made him disenchanted with academia, however, and he discontinued his education around the time he was fifteen or sixteen.

In order to travel safely and affordably in France, Psalmanazar first pretended to be an Irish pilgrim on his way to Rome. After learning English, forging a passport, and stealing a pilgrim's cloak and staff from the reliquary of a local church, he set off, but he soon found that many people he met were familiar with Ireland and were able to see through his disguise. Deciding that a more exotic disguise was needed, Psalmanazar drew upon the missionary reports about East Asia that he had heard of from his Jesuit tutors and decided to impersonate a Japanese Christian convert. At some point he further embellished this new persona by pretending to be a "Japanese heathen". Due to a lack of Western knowledge of Japanese cultures, Psalmanazar displayed fictitious customs to convince the public of the authenticity of his background. These so-called customs included eating raw meat spiced with cardamom and sleeping while sitting upright in a chair.

Having failed to reach Rome, Psalmanazar travelled through various German principalities between 1700 and 1702. In the latter year, he appeared in the Netherlands, where he served as an occasional mercenary and soldier. By this time, he had shifted his supposed homeland from Japan to the even more obscure Formosa (Taiwan), and had developed more elaborate customs, such as following a foreign calendar, worshipping the Sun and the Moon with complex propitiatory rites of his own invention, and even speaking an invented language.

In late 1702, Psalmanazar met the Scottish priest Alexander Innes, who was the chaplain of a Scottish army unit. Afterwards Innes claimed that he had converted the heathen to Christianity and christened him George Psalmanazar (after the Assyrian king Shalmaneser V, who is referenced in the Bible). In 1703, they left via Rotterdam for London, where they planned to meet Anglican clergymen.

When they reached London, news of the exotic foreigner with bizarre habits spread quickly and Psalmanazar achieved a high level of fame. His appeal not only derived from his exotic ways, which tapped into a growing domestic interest in travel narratives describing faraway locales, but also played upon the prevailing anti-Catholic and anti-Jesuit religious sentiment of early 18th-century Britain. Central to his narrative was his claim to have been abducted from Formosa by malevolent Jesuits and taken to France, where he had steadfastly refused to become a Catholic. Psalmanazar declared himself to be a reformed heathen who now practised Anglicanism. He became a favourite of the Bishop of London Henry Compton and other esteemed members of London society.

Building upon this growing interest in his life, Psalmanazar published a book in 1704, An Historical and Geographical Description of Formosa, an Island subject to the Emperor of Japan. This book purported to be a detailed description of Formosan customs, geography and political economy; it was in fact completely fabricated. The "facts" contained in the book are an amalgam of other travel reports, especially influenced by accounts of the Aztec and Inca civilisations in the New World, and by embellished descriptions of Japan. Thomas More's Utopia may also have served as an inspiration. Some of his claims about Japanese religion seem to also be derived from a misinterpretation of the Chinese idea of three teachings, as he claims that there were three different forms of "idolatry" practiced in Japan.

According to Psalmanazar, Formosa was a prosperous country with a capital city called Xternetsa. Men walked naked except for a gold or silver plate to cover their genitals. Their main food was a serpent that they hunted with branches. Formosans were polygamous and husbands had a right to eat their wives for infidelity. They executed murderers by hanging them upside down and shooting them full of arrows. Every year they sacrificed the hearts of 18,000 young boys to gods, and their priests ate the bodies in an act of cannibalism. They used horses and camels for transport, and dwelled underground in circular houses.