A notification system of a vehicle includes a sensing unit that detects an object outside the vehicle or detects an operational status of a function of the vehicle; an output unit; and a controller. The controller is configured to determine whether a touch has been detected on an interior handle of a door of the vehicle. If a touch is detected on the interior handle, the controller determines that an object outside the vehicle detected by the sensor is within a predetermined distance in a rearward direction from the door on which the touch was detected, or determines that an operational status of a function of the vehicle detected by the sensor indicates that the function is not yet complete; and controls the output unit to output a notification corresponding to the detected object outside the vehicle or the detected operational status of the function of the vehicle.