Thermoelectrochemistry as a branch of electrochemistry like photoelectrochemistry is reviewed in an integral treatment of the subject. Especially modern thermoelectrochemistry is focused on new techniques to vary the temperature as an independent variable. This review based on a definition of modern thermoelectrochemistry includes all the classical work which contributes to the formation of modern thermoelectrochemistry, among them high-temperature electrochemistry, subcritical- and supercritical electrochemistry and in-situ electrochemical calorimetry. The main focus is on modern techniques like fast electrode heating by lasers or by alternating current as well as on heating of solution spots by microwaves and related methods. Here the state of the art in modern thermoelectrochemistry is critically reviewed for the first time.