A steering system for front and rear wheels of a motor vehicle wherein the steering ratio of the rear wheels to the front wheels is variable dependent on the speed of the motor vehicle. The steering system includes a steering wheel, front wheels, a first assembly for steering the front wheels, rear wheels, a second assembly for steering the rear wheels, and a third assembly which transmits the direction and extent of steering of the front wheels to the second assembly, a fourth assembly controls the steering ratio between the front and rear wheels in response to a signal indicative of the speed of the motor vehicle or a signal related to the speed of the motor vehicle. Each of the rear wheels has a kingpin having a central line which has an extension which is positioned rearwardly of a point where a vertical line passing through the center of an axle of the rear wheel intersects the ground on which the motor vehicle is placed. The steering system provides a facilitated compensating operation of the steering wheel by increasing a reactive force against steering which allows the driver to return the steering wheel of its own accord without excessively turning the steering wheel upon vehicle deceleration, and reducing the reactive force to allow the driver to turn the steering wheel of its own accord upon vehicle acceleration.