William C. "Bill" Brainard (born c. 1935) is an American economist. He is the Arthur Okun Professor Emeritus of Economics at Yale University,^[1] and he served as the provost of the university from 1981 to 1986. Brainard is the namesake of the William C. Brainard chair, which current Yale provost Ben Polak holds.^[2] Brainard earned both his economics M.A. (1959) and Ph.D. (1963) at Yale. He has been teaching at Yale since 1962.^[2]

Along with his frequent collaborator James Tobin, Brainard developed the theory of Tobin's q. The concept first appeared in Brainard and Tobin's 1968 article "Pitfalls in Financial Model Building"^[3] The letter "Q," however, was not introduced until Tobin's 1969 article "A general equilibrium approach to monetary theory."^[4] So, while references to "Q theory" generally carry only Tobin's name, Brainard and Tobin jointly introduced the concept.^[5] Brainard was co-editor with George Perry of the Brookings Papers on Economic Activity from 1980 through 2007, and continues to serve on its advisory panel. Brainard's fields of interest are: Microeconomics, microeconomics and macroeconomic theory, monetary theory and policy, market valuation of firms, and models of financial markets.^[6]