Hans Karl August Simon von Euler - Chelpin (15 February 1873 – 6 November 1964) was a German born Swedish biochemist. He won the Nobel Prize in Chemistry in 1929 with Arthur Harden for their investigations on the fermentation of sugar and fermentative enzymes.

He was professor of general and organic chemistry at Stockholm University 1906 - 1941 and director of its Institute for organic chemical research 1938 - 1948.

von Euler - Chelpin was married to the botanist and geologist Astrid Cleve (daughter of the Uppsala chemist Per Teodor Cleve) and was the great - great - great grandson of Leonhard Euler and father of Ulf von Euler, who was awarded the Nobel Prize in Physiology or Medicine in 1970.