Karl Arnold variously Carl Johann Moritz Arnold or Johann Karl Moritz Arnold (March 12, 1853, Uffenheim - June 24, 1929, Hanover) was a German chemist and mountaineer.
He served as Director and briefly as Vice-Chancellor of the Institute of Chemistry at the University of Veterinary Medicine Hanover.
His published works on organic chemistry were of importance to veterinarians, medical students and pharmacists.
He was also an accomplished alpinist and chairman of the Hanover section of the German-Austrian Alpine Association.