Baron Jacob Adolphe Reinach (17 April 1840, Frankfurt - 19 November 1892, Paris), known as Jacques de Reinach was a French banker of Jewish German origin, involved in many major financial affairs of the era and finally brought down by the Panama scandal. He was the son of Clementine Oppenheim (1822–1899) and her husband Adolphe de Reinach (1814–1879), Belgian consul in Frankfurt, ennobled in Italy in 1866 and then confirmed as a noble by William I of Germany.
He settled in Paris at the end of the 1850s and in 1863 founded the banque Kohn-Reinach with his brother in law, the international financier Édouard Kohn. On 6 May 1863 he married his first cousin Fanny Emden. Their children were Henriette-Clémentine (who married Joseph Reinach), Lucien and Juliette-Maximilienne. He served in the National Guard during the Siege of Paris (1870–1871) and was naturalised as a French citizen in 1871.