Sir Hans Adolf Krebs (German pronunciation: [ˈhans ˈaːdɔlf ˈkʁeːps] (audio speaker iconlisten), /krɛbz, krɛps/; 25 August 1900 – 22 November 1981) was a German Jewish scientist who became a naturalised British citizen. He was a physician and biochemist.

Krebs researched metabolism. He is famous because he discovered the urea cycle and the citric acid cycle (also called the Krebs Cycle). Krebs won the Nobel Prize in Physiology or Medicine for this, in 1953.