Jean Joseph Ernest Theodore Gambart (12 October 1814 – 12 April 1902) was a Belgian-born English art publisher and dealer who dominated the London art world in the middle of the nineteenth century.
Gambart was born in Kortrijk, the son of a printer, binder and bookseller. By the age of 19, he had moved to Paris where he established his own print and papermaking business. He soon became known to the well-established Goupil print publishers, for whom he moved to England in 1840 to establish a branch in London. He soon struck out on his own again in 1842, this time in partnership with one Mr. Junin, to form the company Gambart & Junin which specialised in the import of art prints from Europe. The company was a success, and by early in 1844, the company was established as publishers as well as importers and exporters.
Gambart soon gained a reputation as a leading publisher of fine art prints. He established fair and mutually beneficial agreements with most of the best known British and European artists of the mid-Victorian period, including Edwin Landseer, John Everett Millais, Rosa Bonheur, Lawrence Alma-Tadema, William Holman Hunt, John Linnell, J. M. W. Turner, David Roberts, Frederick Goodall, Dante Gabriel Rossetti, Ford Madox Brown and William Powell Frith. He was a friend to many of these artists, and helped establish the reputation of some. For example, in 1855, he brought Rosa Bonheur to England with her monumental piece, The Horse Fair, which he purchased and which she showed to Queen Victoria at Windsor Castle in a private audience. For the same visit, he arranged a sojourn to Scotland where Bonheur made sketches for later works. He published many of her paintings as steel engraved reproductions. Through his efforts, she became better known in England than her native France.