Thomas Firmin (June 1632 – 1697) was an English businessman and philanthropist, publisher and unitarian member of the Church of England.
Firmin was born to Puritan parents, Henry and Prudence Firmin in Ipswich. Henry Firmin was a parishioner of Samuel Ward, the Puritan incumbent of St. Mary-le-Tower, by whom in 1635 he was accused of erroneous tenets. Thomas Firmin as a young man sent to London and apprenticed to a girdler and mercer who attended the services of John Goodwin at St Stephen Coleman Street; he took down Goodwin's sermons in shorthand.
Setting up in business on his own, in Lombard Street, he met generally latitudinarian Anglicans (Whichcote, John Worthington, John Wilkins, Edward Fowler, and Edward Tillotson). He also became acquainted with John Biddle, who would become an important practical influence. He married in 1660.
Firmin's first philanthropic experiment was occasioned by the trade disorganisation in 1665, the year of the Great Plague. He provided employment at making up clothing for hands thrown out of work. During the Great Fire of London (1666) his Lombard Street premises were burned. He secured temporary accommodation in Leadenhall Street, and in a few years was able to rebuild in Lombard Street, and to carry on his business with increased success. In 1676 he left the management of the concern in the hands of his nephew and partner, Jonathan James (son of his sister Prudence), who had been his apprentice; he was then worth about £9,000. Since about 1673 he had been a governor of Christ's Hospital.
Early in 1676 he started a workhouse in Little Britain, for the employment of the poor in the linen manufacture;’ he built new premises expressly for it. Tillotson suggests that Firmin was influenced by the example of Thomas Gouge. Firmin employed as many as seventeen hundred spinners, besides flax-dressers, weavers, at the market rate (a sixteen-hour day for 6d.), but with some bonuses in kind. He made arrangements for the comfort and cleanliness of his hands, and for the training of children from the streets. He printed large editions of a Scripture Catechism (probably by Edward Fowler), and gave rewards to those who learned it.