Abstract: A cylinder lock for a rotary switch having a rotor, a stator surrounding the rotor and an engagement sleeve surrounding the stator. The engagement sleeve is attached to the fixed portion of the rotary switch and the stator is coupled to the movable portion thereof. Separate latching devices are provided between the stator and engagement sleeve and between the rotor, stator and engagement sleeve. Sets of tumblers are also provided between the rotor and stator and the rotor has a key slot, the position of which indicates the switch position. Insertion and rotation of the key rotates the rotor, disengaging the tumblers and the latching device between the rotor, stator and sleeve, permitting the rotor to rotate alone through a predetermined angle. Further, torque applied to the key causes the latching device between the stator and sleeve to disengage, rotating the stator and the rotary switch to the new switch position at which the stator-sleeve latching device re-engages in that new position.