From the British Museum website:
International print publishing firm which expanded into dealing in and exhibiting contemporary art. Established in France, but soon expanded with branches under various managers in other centres. It traded under a number of different names at different addresses, see below. For prints published by the firm, the name and address that appear on the print are entered in Inscription field of the catalogue entry. Additional biographical database entries are used for the firm at different stages of its history.

1827 founded by Adolphe Goupil (1806-1893), in partnership with John Arrowsmith (q.v.)
1829-December 1840/January 1841: in partnership with Henry Rittner (q.v.)
1841-1850: in partnership with Théodore Vibert (q.v.);
1841 Branch opened in London under Gambart (then under Charles Obach from 1868).
1845 Branch in New York (sold to its manager Michael Knoedler in 1857)
1850-1884: Goupil & Cie; branches in Berlin by 1862, Vienna 1865, Brussels1866
1861: in partnership with Léon Boussod (1826-1896, associated since 1856), and with Vincent van Gogh (uncle of the painter) in the Hague. Theo van Gogh ran the branch of the firm in Boulevard Montmartre.
1884-1919: Boussod, Valadon & Cie (after Goupil's retirement, although the firm continued to be known familiarly by his name); Boussod's son-in-law René Valadon (1848-1921) had been associated since 1878. Boussod's sons Etienne (1857-1918) and Jean (1860-1907), and another son-in-law, Léon Avril (1856-1942) were also involved in the business, the former running the branch at at the Place de l'Opéra. In 1886, photographic studio and printing press set up by Léon Boussod at Asnières.