Thomas Nelson is a publishing firm that began in West Bow, Edinburgh, Scotland, in 1798, as the namesake of its founder. It is a subsidiary of HarperCollins, the publishing unit of News Corp. It describes itself as a "world leading publisher and provider of Christian content".

Its most successful title to date is Heaven Is for Real. In Canada, the Nelson imprint is used for educational publishing. In the United Kingdom, it was an independent publisher until 1962, and later became part of the educational imprint Nelson Thornes.

Thomas Nelson Sr. founded the shop that bears his name in Edinburgh in 1798, originally as a second-hand bookshop at 2 West Bow, just off the city's Lawnmarket, recognizing a ready market for inexpensive, standard editions of non-copyright works, which he attempted to satisfy by publishing reprints of classics. By 1822, the shop had moved to 9 West Bow, and a second shop had opened at 230 High Street.

In 1835, the shop became a company, first as Thomas Nelson & Son when William joined, and in 1839 became Thomas Nelson & Sons when Thomas Jr. entered the business. Thomas Sr. died in 1861 and is buried in the extreme north-west corner of Grange Cemetery in Edinburgh. William concentrated his talents on the marketing side, and Thomas Jr. devoted his to editing and production. In the mid-19th century, Walter Scott Dalgleish was an editor with the company.

The firm became a publisher of new books and, as the 19th century progressed, it produced an increasingly wide range of non-religious materials; by 1881, religion accounted for less than 6 per cent of the firm's output. Its Hope Park Works, located just east of the Meadows in Edinburgh, burned down in 1878, and the city council allowed temporary accommodation on the Meadows. In appreciation, the company funded the stone pillars at the east end of Melville Drive, close to Hope Park.

William Nelson died in 1887, and Thomas Jr. died in 1892. They were succeeded by George Brown, Thomas's nephew, who directed the company until Thomas III and Ian, Thomas Jr.'s sons, joined him and John Buchan as partners. Buchan, employed by the firm until 1929, dedicated his novel The Thirty-Nine Steps to Thomas III (Thomas Arthur Nelson) in 1914.

In 1915, Thomas Nelson took over the art publishing house T.C. & E.C. Jack, based in Edinburgh and London. T.C. & E.C. Jack was founded in 1859 by Thomas Cheskolm Jack (1831–1886). After his death in 1886, his sons Thomas Chater Jack (1863–1939) and Edwin Chisholm Jack (1865–1939) took over the publishing house. T.C. & E.C. Jack was continued as an imprint by Thomas Nelson.

Ian Nelson took over as head of the family firm after Thomas Nelson III's death in action in 1917, during World War I.^{[citation needed]}