A vehicle steering system is configured to avoid contact between wheels and wheel housings when the wheels are steered and to enlarge the maximum steering angle. The vehicle steering system has a steering knuckle that supports a wheel for rotation about a wheel axis and a pivotal movement about a steering axis. The steering knuckle is coupled to a first end part of an extension link. A second end part of the extension link is connected to an arm through a control rod. The extension link is pivotally sustained around a steering axis. The arm is connected to a front end of a knuckle arm through a tie rod. When the arm turns, the second end part of the extension link is pulled inside through the control rod, and the steering knuckle situated on rear end of the control rod is pushed outwardly. At the same time, the arm steers the steering knuckle through the tie rod.