A lock cylinder having a cylinder housing in which a cylinder core is rotatably disposed and which can be locked with the cylinder housing via spring-loaded tumblers upon the withdrawal of a key from a key duct of the cylinder core. A bearing sleeve encloses the cylinder housing and the cylinder housing is rotationally fixed by means of an overload coupling in this bearing sleeve. A rotary connecting element, arranged behind the lock cylinder, leads to a locking mechanism which and can be connected with the cylinder core by a separating coupling. The lock cylinder, while maintaining its overload protection, becomes suitable for the rotational control of a locking mechanism which is arranged separately of the lock cylinder. The separating coupling, irrespective of the locking condition of the lock, remains permanently engaged during rotating movements of the cylinder core with respect to the rotationally fixed cylinder housing and can be automatically disengaged by a control device only in the case of an overload rotation of the cylinder housing with respect to the bearing sleeve, and before an opening angle of rotation of the cylinder core is reached.