A roll stabilizer for a motor vehicle includes a torsion bar and a vibration damper located on the torsion bar. The vibration damper is configured to vibrate relative to the torsion bar. The vibration damper includes two half-shells formed together about the torsion bar. Damper elements are disposed between the half-shells. The damper elements can be adjusted via an adjustment component to alter the rigidity of the damper elements.