A vehicular rear window assembly includes a window panel comprising an inner side and an outer side. A spoiler includes (i) a base portion that is adhesively attached at and along an upper region of the outer side of the window panel and (ii) a cover portion that is attached at the base portion. The vehicular rear window assembly, with the spoiler adhesively attached at and along the upper region of the outer side of the window panel, is configured for mounting at a rear portion of a cabin of the vehicle. With the vehicular rear window assembly mounted at the rear portion of the cabin of the vehicle, the inner side is toward the cabin of the vehicle and the outer side and the spoiler are exterior of the vehicle.