3 Bromo-1-naphthoic acid, 4-bromo-1-naphthoic acid, 5-bromo-1-naphthoic acid, and their ethyl esters have been prepared. The kinetics of alkaline hydrolysis is ethanol-water (85:15 W/W) of these esters, together with the unsubstituted ester, have been studied, using stainless steel reaction vessels, over the temperature range 25-65°C. Arrhenius frequency factors and energies of activation have been determined. The frequency factors have been shown to be constant within a small experimental error. Relative free energies, heats, and entropies of activation for these hydrolyses have been evaluated and their significance discussed. Hammett substituent constants for the bromo-substituent in the 3, 4, and 5 positions of naphthalene have been calculated and discussed.