17 December 1724 in Hanover, died 1 May 1793 in Hanover), often known as J.G.R. Andreae or I.G.R. Andreae, was a Hanoverian natural scientist, chemist, geologist, court pharmacist (Hofapotheker) and alchemist in the Age of Enlightenment. Internationally noted as a polymath, he was known throughout Europe particularly for his extensive natural history collections and for his pioneering and influential scientific work on soil and their uses for modern agriculture. He was a friend of many of the great scientists of the day, such as Benjamin Franklin, Pieter van Musschenbroek and George Shaw.