Founder of Guys Hospital, London, the son of a lighterman and coal-dealer at Southwark. After serving an apprenticeship of eight years with a bookseller, he in 1668 began business on his own account. He dealt largely in Bibles, which had for many years been poorly and incorrectly printed in England. These he at first imported from Holland, but subsequently obtained from the university of Oxford the privilege of printing. Thus, and by an extremely thrifty mode of life, and more particularly by investment in government securities, the subscription of these into the South Sea Company, and the subsequent sale of his stock in 1720, he became master of an immense fortune. He died unmarried on the 17th of December 1724. In 1707 he built three wards of St. Thomass Hospital, which institution he otherwise subsequently benefited; and at a cost of £18,793, 16s. he erected Guys Hospital, leaving for its endowment £219,499; he also endowed Christs Hospital with £400 a year, and in 1678 endowed almshouses at Tamworth, his mothers birthplace, which was represented by him in parliament from 1695 to 1707. The residue of his estate, which went to distant relatives, amounted to about £80,000.
See A True Copy of the Last Will and Testament of Thomas Guy, Esq. (London, 1725); J. Noorthouck, A New Hist. of London, bk. iii. ch. i. p. 684 (1773); Nichols, Literary Anecdotes, iii. 599 (1812); Charles Knight, Shadows of the Old Booksellers, pp. 323 (1865); and A Biographical History of Guys Hospital, by S. Wilkes and G. T. Bettany (1892).