A passenger reminder system for reminding a driver-caregiver, upon exiting a vehicle, that a passenger remains in the vehicle. Embodiments of the passenger reminder system generally comprise one or more straps or other barriers used to connect a driver's seat belt to the interior of the driver side front door. When the driver's door is open, the strap of the passenger reminder system extends from the seat belt to the interior of the driver's door, impeding the driver-caregiver from exiting the car. This hindrance reminds the driver-caregiver that another passenger is onboard and prompts the removal of the passenger.