Harold Demsetz (/ˈdɛmsɛts/; May 31, 1930 – January 4, 2019)[1] was an American professor of economics at the University of California at Los Angeles (UCLA).

Demsetz grew up on the West Side of Chicago, the grandchild of Jewish immigrants from central and eastern Europe.

Demsetz was a fellow of the American Academy of Arts and Sciences, a director of the Mont Pelerin Society, and a past (1996) president of the Western Economics Association.

His expository style is devoid of mathematical formalism to an extent unusual for someone who began his career after 1950.

His principal influences include Frank Knight and a number of colleagues: Armen Alchian, Ronald Coase, Aaron Director, and George Stigler.