Melchior Neumayr (24 October 1845 – 29 January 1890) was an palaeontologist from Austria-Hungary and the son of Max von Neumayr, a Bavarian Minister of State. He specialized on the Jurassic and Cretaceous of the Alps. Neumayr introduced the concept of the Tethys sea in 1885, calling it the Jurassic seaway. The name "Tethys" was given by his father-in-law Eduard Suess.