Abstract: The invention relates to a device for rotating a rotor of a wind turbine. Here, the wind turbine has the rotor, a tower, a nacelle with a machine frame, and a hub on which at least one rotor blade can be mounted. The rotor is arranged so as to be rotatable relative to the nacelle about an axis of rotation. The wind turbine furthermore has a locking device for blocking a rotational movement of the rotor about the axis of rotation. The device has at least one first displacement unit which is fastened to the machine frame. The first displacement unit also has a fastening device by means of which the first displacement unit can be detachably fastened to the rotor. Finally, the fastening device is actuable, in particular electrically and/or hydraulically actuable. The invention furthermore relates to a system for rotating one rotor of the wind turbine. The invention finally relates to a method for rotating the rotor of the wind turbine by means of the device or by means of the system.