A balancing adapter for clamping a rotor to a machine part of balancing machine that rotates about an axis of rotation. The balancing adapter has a main body having a central accommodating opening for the rotor, a collet chuck having clamping elements for detachably retaining the rotor in the accommodating opening, and an actuating device for moving the clamping elements between a clamping position and a releasing position. In order to enable positionally accurate and reproducible accommodation and retention, the clamping elements of the collet chuck are supported on a guiding surface on the main body.