Thomas Fyshe Palmer (1747–1802) was an English Unitarian minister, political reformer and convict.
Palmer was born in Ickwell, Bedfordshire, England, the son of Henry Fyshe who assumed the added name of Palmer because of an inheritance, and Elizabeth, daughter of James Ingram of Barnet.
Palmer was educated at Eton College and Queen's College, Cambridge from 1765, with the purpose of taking holy orders in the Church of England. He graduated B.A. in 1769, M.A. in 1772, and BD in 1781. He obtained a fellowship of Queens' in 1781, and officiated for a year as curate at Leatherhead, Surrey. While at Leatherhead he was introduced to Samuel Johnson, and dined with him in London; but he had become disillusioned with some aspects of the Church of England.
Palmer then read in Joseph Priestley's works, and became a Unitarian. For the next ten years Palmer preached Unitarianism to congregations in Dundee and other Scottish towns. A Unitarian society had been founded by William Christie, a merchant, at Montrose, and Palmer offered his services as a preacher (14 July 1783). In November 1783 Palmer reached Montrose, and remained as Christie's colleague till May 1785. He then moved to Dundee to become pastor of a new Unitarian society there, and he founded a Unitarian church. He preached also in Edinburgh, Glasgow, Arbroath, and Forfar, and formed further Unitarian societies. In 1789 he took temporary charge of the society at Newcastle. In 1792 his sermons in Edinburgh attracted attention, and pamphlets were published in refutation of his doctrines.
When agitation for political reform began in 1792, Dundee became one of its centres in Scotland. A society called the 'Friends of Liberty' was formed in 1793, and met in the Berean meeting-house in the Methodist Close, beside the house where Palmer lived in the Overgait. The society was composed mainly of working men. One evening in June 1793 Palmer was attended a meeting, when George Mealmaker, weaver in Dundee, brought a draft of an address to the public which he purposed circulating as a handbill. Palmer revised it, modifying it to a complaint against the government for war taxation, and a claim for universal suffrage and short parliaments. The address was sent to be printed in Edinburgh in July 1793. The authorities were alarmed, and decided to meet an anticipated revolution in time; and, in the belief that they were attacking a revolutionary leader, Palmer was arrested in Edinburgh on 2 August on a charge of sedition as the author of the document.