Abstract: A keyboard lock mechanism is disclosed herein for preventing all or some of the keys or pushbuttons on a telephone from being depressed which includes a mounting plate attached detachably or permanently to the body or case of the telephone and having a central opening therein exposing the full keyboard of keys normally carried on the telephone body. A movable cover is pivotally or slidably carried on the mounting plate for selective positioning over the keys of the keyboard so that the keys are inaccessible. A lock having a movable latch releasably secures the cover over the keys or pushbuttons. Attachments are provided on the mounting plate for securing the mechanism onto the telephone body.