Abstract Electrochemical properties of silicate minerals govern their behavior in processes such as flocculation and enhanced oil recovery that can occur at elevated temperatures. Knowledge of these properties as a function of temperature can be helpful in developing an understanding of the role of these interfacial properties at non-ambient temperatures. The zeta potential of sodium kaolinite and quartz has been determined as a function of temperature in this work. Both systems exhibited markedly different behavior at higher temperatures and also exhibited significant hysteresis. The results were examined in terms of possible dissolution of the minerals and surface reactions at different temperatures.