Ronald William Shephard (November 22, 1912 – July 22, 1982) was Professor of Engineering Science at the University of California, Berkeley. He is best known for two results in economics, now known as Shephard's lemma and the . Shephard proved these results in his book Theory of Cost and Production Functions (Princeton University Press, 1953), which Dale W. Jorgenson, in the preface of a reprint, called "the most original contribution to economic theory of all time."