A steering lock system for locking a steering system of an automotive vehicle equipped with an automatic transmission. The steering lock system is comprised of a selector position sensor for detecting a selected position of a selector lever for the automatic transmission. The selector position sensor is adapted to produce a parking position signal when the selector lever is at a Part position. A key cylinder is rotatable to take a LOCK position by an ignition key insertable into the key cylinder. The ignition key is enabled to be pulled out of the key cylinder at the LOCK position, upon which a steering shaft is locked. The ignition key is disabled from being pulled out of the key cylinder upon absence of the parking position signal from the selector position sensor while is enabled to be pulled out of the key cylinder only in response to the parking position signal from the selector position sensor, thereby improving reliability of operation of the steering lock system.
