Johann Jacob Baeyer (born 5 November 1794 in Berlin, died 10 September 1885 in Berlin) was a German geodesist and a lieutenant-general in the Royal Prussian Army. He was the first director of the Royal Prussian Geodetic Institute and is regarded as the founder of the International Association of Geodesy. He was the father of the Nobel Prize–winning chemist Adolf von Baeyer. Baeyer was a Lutheran.