Abstract: Improved response in an ambient temperature compensated thermal overload relay is obtained by providing a bimetal element (2) wherein the main bimetal section (4) is coupled through a reversed compensating bimetal section (6) to a heat sink mounting base (8) either directly or through a heat transfer control member (18) and placing the heater (10) that is energized by the overload current only adjacent the main bimetal section (4). With this arrangement, the main bimetal section (4) bends in the switch tripping direction and the compensating bimetal section (6) bends in the subtractive direction in response to temperature change therein to reduce the net deflection for ambient temperature compensation under normal operating conditions and gradual small overload conditions.