Laszlo Lorand (23 March 1923 – 6 December 2018) was a Hungarian-American biochemist who studied clotting of blood and other bodily fluids. A professor emeritus in cell and molecular biology at the Feinberg School of Medicine, Lorand was a longtime professor in the departments of chemistry and molecular biosciences at Northwestern University before transferring to Northwestern's medical school. Lorand was a co-discoverer of the substance that later became known as factor XIII. He was a member of the National Academy of Sciences.