Road accidents and vehicle theft are rising concerns, especially among two-wheeler users. This project presents a Smart Bike Accident Notification and Theft Detection System that enhances rider safety and bike security through real-time monitoring and automated alerts. The system integrates an MPU6050 accelerometer-gyroscope sensor to detect accidents based on tilt angle variations, and a GPS module (NEO-6M) to monitor the bike’s location. A GSM module (SIM900) is used to send SMS alerts and initiate calls to predefined emergency contacts upon detecting an accident or unauthorized movement. The system also includes a theft detection feature that activates when the bike is parked. If the bike is moved beyond a set distance (e.g., 10 m) from its parked GPS location, the system considers it a theft attempt and alerts the owner with the current coordinates. A buzzer and LED indicators provide local alerts, while a relay module controls the engine to disable it during emergencies or theft. This Arduino-based prototype offers a low-cost, reliable solution for enhancing personal safety and vehicle protection. It is especially suitable for developing countries like Sri Lanka, where smart solutions can significantly reduce emergency response time and discourage theft. Furthermore, to ensure uninterrupted operation during main power failures, the system is equipped with a dedicated backup power unit utilizing rechargeable lithium-ion batteries.