A gap fairing for a tractor-trailer. A fairing body is attached to a chassis of the tractor, independently of the cab thereof and within a gap between a cab of the tractor and the trailer. The fairing body has side portions, extending rearwardly from a front portion, adjacent the cab of the tractor, toward the trailer and top portion. A clear panel can be located in at least the side portion of the fairing body located at the passenger side to enable the driver to view the trailer through the rear window of the tractor and the clear panel. A separation space between the front of the fairing body and the cab can be sealed by a sealing element that is at least in part one of resilient and flexible so as to allow relative motion between the fairing body and the cab.