Thermal stress is one of the most common reasons for failure in power electronic circuits, battery protection circuits, and motor driver circuits. Prolonged overheating can result in decreased efficiency, damaged components, or a complete circuit breakdown. This paper describes the design and simulation of a simple and low-cost temperature-protection circuit for a MOSFET using an NTC thermistor and an LM358 operational amplifier as a comparator. The thermistor circuit continuously tracks temperature changes, and a potentiometer is used to set the temperature threshold. If the temperature measured exceeds the set threshold, the comparator output activates a control circuit driven by a transistor to switch off the load via anIRFZ44N power MOSFET. The normal and faulty conditions are indicated by LEDs and a buzzer. The simulation of the proposed system using Proteus software has confirmed the functionality and response characteristics of the circuit. The simulation results show that the circuit provides effective thermal protection with a fast response and a simple circuit design, making it suitable for use in power modules, battery protection circuits, motor drivers, and solar charge controllers.