Adolf Weil (February 7, 1848, Heidelberg – July 23, 1916, Wiesbaden) was a German physician after whom Weil's disease is named.
Weil studied medicine at the University of Heidelberg, and afterwards furthered his education in Berlin and Vienna. From 1872 to 1876 he was an assistant to Friedrich Theodor von Frerichs (1819-1885) in Berlin. In 1886 he was appointed professor of special pathology and therapy at the University of Dorpat, but resigned shortly afterwards, after contracting tuberculosis of the larynx and permanently losing his voice . After 1893 he lived and worked in Ospitaletto, San Remo and Wiesbaden.
In 1913, in collaboration with Emil Abderhalden (1877-1950) he isolated an alpha-amino acid known as norleucine. Among his written works was an influential treatise on the auscultation of arteries and veins, and the manual Handbuch und Atlas der topographischen Percussion. Shortly after receiving news that Weil's disease was caused by a spirochete, he died of acute hemoptysis.