Sir Joseph Prestwich FRS FGS (12 March 1812 – 23 June 1896) was a British geologist and businessman, known as an expert on the Tertiary Period and for having confirmed the findings of Boucher de Perthes of ancient flint tools in the Somme valley gravel beds.

Born in Clapham, Prestwich was educated in Paris and Reading before entering University College, London where he studied chemistry and natural philosophy.

In 1858, Prestwich was persuaded by Hugh Falconer to visit Abbeville, where Boucher de Perthes had claimed to have found flint tools in the gravel deposits of the valley of the Somme, thus establishing the antiquity of man.

In company with Sir John Evans, Prestwich visited the gravel beds of St Acheul and confirmed the observations of Boucher de Perthes.

Prestwich's report on the matter was published in the Proceedings of the Royal Society for 1859-1860: It is claimed by some authorities that this publication marks the birth of modern scientific archaeology.