A torsional vibration damper has a drive-side transmission element and an output-side transmission element rotatable relative thereto that is connected to the drive-side transmission element via a damping device. The damping device includes a first gear element and a second gear element that are in a meshed engagement with each other via a first set of teeth and a second set of teeth, respectively. The sets of teeth for each gear element is provided on the axial sides of the gear elements. A positioning device axially positions the gear elements relative to each other for adjusting the penetration depth of the meshed engagement of the first and second sets of teeth.