António Nunes Ribeiro Sanches (7 March 1699, Penamacor – 14 October 1783, Paris) was an 18th-century Portuguese physician, philosopher and encyclopédiste. He was a cristão novo of Jewish descent, probably a practising Jew. After he studied in the universities of Coimbra and Salamanca, Sanches moved to London. He then went to Leyden University where he completed his formation under the direction of Herman Boerhaave. He was among the three physicians that empress Anna of Russia asked the latter to recommend to her in 1731.