Transport accident is one of the common cause of death in Malaysia and usually is caused by vehicle exceeding the speed limit set by the authorities. Although Automated Enforcement System is implemented to monitor vehicle speed, it is only installed at specific locations, and the speed cannot be tracked throughout the driving journey. Hence, an IoT-Based Vehicle Speed Monitoring System (VSMS) is developed to retrieve the vehicle speed information from the Onboard Diagnostic II sensor to follow speed limits throughout the driving journey. The developed VSMS is a plug-and-play system that can be easily implemented on any compatible vehicle. When the vehicle exceeds the speed limit, a reminder text alert will be displayed in front of the driver. A triggered email on the overspeeding activity could also be sent to the user for monitoring. By implementing VSMS, the drivers can save road users’ lives, including theirs, by slowing down their vehicles.