The techniques of this disclosure relate to a vehicle-occupancy alert system. The system includes a controller circuit configured to receive occupant data from an occupancy-monitoring sensor configured to detect a presence of one or more objects inside a vehicle. The controller circuit is also configured to determine whether an operator of the vehicle has exited the vehicle based on the occupant data. The controller circuit is also configured to determine based on the occupant data that the one or more objects remain inside the vehicle for a time exceeding a first threshold after the operator has exited. The controller circuit is also configured to output an alert indicating the one or more objects remain inside the vehicle when the time exceeds the first threshold. The system can improve passenger safety by alerting the vehicle operator that a child remains in the vehicle unattended before the operator moves away from the vehicle.