Abstract: Anti-sway apparatus for use on a vehicle such as a car, truck, or trailer. The vehicle includes an elongated frame structure conventionally carried on a wheel-mounted support structure. The apparatus includes a rigid beam connected to one of the vehicle structures, transversally of the frame structure's long axis, for shifting angularly with the structure to which it is connected and substantially vertically with respect thereto. The beam is coupled to the other vehicle structure by an elastic belt which acts to resist angular movement, about its long axis, with respect to the support structure.