An antenna assembly for mounting an antenna on a vehicle body, especially upon the roof of a vehicle, in which the assembly has a base body of metal with a threaded projection passing through a hole in a wall of the vehicle body. A housing of plastic encloses the antenna components mounted upon a plate-shaped portion of the base body and a seal is provided between the base body and the vehicle body and seals around the opening between the base body and the wall of the vehicle. The seal can be injection molded and molded onto the base body in the injection-molding process.