Pure Theory of Law is a book by jurist and legal theorist Hans Kelsen, first published in German in 1934 as Reine Rechtslehre, and in 1960 in a much revised and expanded edition. The latter was translated into English in 1967 as Pure Theory of Law. The title is the name of his general theory of law, Reine Rechtslehre.

Kelsen began to formulate his theory as early as 1913, as a "pure" form of "legal science" devoid of any moral or political, or at a general level sociological considerations.