Abstract: The invention is a lockable electrical switch including a cylindrical plug mounted within a shell for rotary movement between locked and unlocked positions and for axial movement between active and inactive positions, the plug defining a keyway and a plurality of tumblerways intersecting therewith. Residing in the tumblerways are tumblers that operatively engage the shell and the plug so as to prevent relative rotation therebetween in the absence of a proper key in the keyway. A movable contact is mounted for movement with the plug and a stationary contact is shaped and arranged so as to be engaged by the movable contact with the plug in both its unlocked and active positions but to be disengaged therefrom with the plug in either of its locked or inactive positions. Closure of the switch by engagement of the contacts requires the use of a key to rotate the plug into an unlocked position.