A steering assistance system for an agricultural vehicle includes a rigid axle on which steerable wheels are mounted and which is mounted so as to float relative to a supporting vehicle structure. The system includes a steering angle sensor for detecting a steering angle of the steerable wheels, a swing angle sensor for determining a swing angle of the rigid axle relative to the supporting vehicle structure, an actuating arrangement for influencing the steering angle, and a control unit that calculates a threshold value permissible for the steering angle depending on the detected swing angle. If the detected steering angle exceeds a tolerance range specified for the threshold value, the control unit executes steering interventions for reducing the steering angle by activating the actuating arrangement to satisfy the threshold value.