Abstract: A side window defogging device for a motor vehicle is described. The device is used in a motor vehicle having: a body structure which includes a windshield and at least one side window disposed rearwardly of the windshield; and a heater system for directing heated air over the inner surface of the windshield. The defogging device is disposed in the path of the heated air and defines an air deflecting surface which is spaced from an adjacent part of the vehicle body structure and which is arranged to deflect approaching heated air towards the inner surface of the side window.