The influence of metal surfaces on inductive (or electrostatic field) substituent effect measurements for surface reactions has been evaluated using image charge theory. Substituent effects have been a valuable tool for determining the electronic properties of transition states fur reactions in many environments but have not received much use or consideration on metal surfaces. An important mechanism by which substituents can alter the activation barrier of a reaction is through local dipole field effects on a charged reaction center. To evaluate the influence of a nearby metal surface, substituent field effects have been modeled by considering a point charge and a dipole, both positioned above a conductive surface, that interact electrostatically with their corresponding images at equal distances below the surface. It has been found that the magnitude of substituent effects for reactions on metal surfaces will be approximately equal to the gas-phase value for geometries in which the substituent is farther from the surface than the reaction center and both are above the image plane. This model was used to describe beta-hydride elimination from ethoxides on Cu(111). This reaction has been found to have a substituent effect that con elates with the reaction energetics of gas-phase alcohol dehydrogenation, a result that is in agreement with the image charge model of the electrostatic influence of the metal.