Griffith Conrad Evans (11 May 1887 – 8 December 1973) was a mathematician working for much of his career at the University of California, Berkeley. He is largely credited with elevating Berkeley's mathematics department to a top-tier research department, having recruited many notable mathematicians in the 1930s and 1940s.

Evans earned his PhD at Harvard in 1910 under Maxime Bôcher with a dissertation on Volterra's Integral Equation, after which he did a post-doc for two years at the University of Rome on a Sheldon Fellowship from Harvard. The experience of working under Vito Volterra shaped his intellectual life and solidified his interest in the application of mathematics to a broad range of fields. Evans became close to Volterra during his time at Rome, being invited on many occasions to lunch with the Volterra family; he would remain in contact with Virginia Volterra, Vito Volterra's niece, until the 1960s.

Evans was appointed assistant professor at Rice University in 1912, with a recommendation letter from Volterra, and promoted to professor in 1916. He married Isabel Mary John in 1917 and they would eventually have 3 children. During his time at Rice, he managed to attract significant mathematicians as visiting professors, such as Szolem Mandelbrojt, Tibor Rado, and Karl Menger. His early research dealt with functional analysis, potential theory, integral equations, and mathematical economics.

In 1934, he moved to University of California, Berkeley to chair the mathematics department. Here, Evans was tasked with improving the department, including the initiation of a graduate program. Much of his success was due to his ability to recruit many notable research mathematicians, including Hans Lewy, Jerzy Neyman, and Alfred Tarski. His own research work was in potential theory and mathematics applied to economics. He chaired Berkeley's department until 1949 and retired in 1955, eventually becoming the namesake of Evans Hall at Berkeley.

Evans first work in mathematical economics, entitled A Simple Theory of Competition a restatement of Augustine Cournot's monopoly/duopoly model. Evans expanded Cournot's work significantly by exploring the analytical implications of a variety of different assumptions as to the behavior and objectives of either the monopolist or the duopolists. His following work, The Dynamics of Monopoly, published in 1924, was one of the first to apply the calculus of variations to economic theory. He frames the same monopolist problem now in an intertemporal framework, that is, instead of seeking immediate profit-maximization, the monopolist aims to make his profits as maximum through an interval of time. His work was followed by his Ph.D. advisee Charles Roos who generalized his monopoly model to a case with multiple competing firms. Roos also managed to express this model within a general equilibrium framework. Roos would also be one of the three founders of the Econometric Society alongside Norwegian economist Ragnar Frisch and American economist Irving Fisher. Evans participated in the foundation of the Society and became one of its first fellows.

The first economist to take notice of Evans' work was Harold Hotelling. He met personally with Evans at a meeting of the American Mathematical Society and was immediately impressed by the scope of his work which he deemed to be a "dawning economic theory" that would bear "to the older theories the relations which the Hamiltonian dynamics and the thermodynamics of entropy bear to their predecessors". At this time, economics was not seen as a mathematical science, and many economists were even doubtful if mathematics could be useful for social sciences in general. As a result, Evans and Roos found only a small audience properly equipped to understand their works. Even so, the more mathematically inclined economists and mathematicians E. B. Wilson, Irving Fisher, Henry Schultz, and Paul Samuelson all recognized the importance of their theory.

Evans main contribution to mathematical economics came in the form of his 1930 textbook Mathematical Introduction to Economics, published by Mc Graw Hill. The book's reception, however, failed to meet Evans' expectations. British economist Arthur L. Bowley, in particular, was very critical stating that the book would be of no use either to the mathematician nor to the economist. R. G. D. Allen, a colleague of Bowley, also criticized the book for not presenting a general economic theory and focusing too much on the resolution of particular problems. Some positive reviews came from Roos and Hotelling, the latter going as far as saying that the book helped "lay a groundwork upon which future contributions to political economy of first-rate importance may be expected to be based".

Despite the mixed reception of his textbook, Evans continued interested in mathematical economics throughout his lifetime. In 1934 he contributed Maximum Production Studied in a Simplified Economic System to the recently established journal Econometrica, published on behalf of the Econometric Society. This work would later be extended by some of his students at Berkeley. He also maintained contact with the field attending seminars and presenting papers at meetings organized by the Econometric Society and the Cowles Commission for Economic Research.