Oskar Langendorff (1 February 1853 in Breslau – 10 May 1908 in Rostock; his first name is sometimes given as "Oscar") was a German physician and physiologist known primarily for his experiments on the isolated perfused heart, the so-called Langendorff Heart apparatus.
In addition, he is credited with discoveries in respiration and in the conduction of impulses in the sympathetic and peripheral nervous system.
His work has served as the basis for the use of retrograde perfusion in science and medicine.