John Jacob Abel (May 19, 1857 - May 26, 1938) was a significant U.S. biochemist and pharmacologist. In 1891 he founded and chaired the first Department of Pharmacology in the United States at the University of Michigan. In 1893 he went on to establish and chair the pharmacology department at Johns Hopkins University (one of the many schools at which he was educated). In 1897 he was the first to isolate epinephrine, also known as adrenaline. He later formulated the idea of the artificial kidney, and, in 1914, isolated amino acids from the blood.

He spent years unsuccessfully searching for the pituitary hormone, unaware that he was in fact looking for several hormones. In 1926 he reported the isolation and crystalization of insulin, though this announcement was met with considerable scepticism, and not generally accepted for many years.

Abel also founded the Journal of Biological Chemistry (1905), and the Journal of Pharmacology and Experimental Therapeutics (1909).