Abstract: A dead bolt lock assembly for securing a sliding door or window and including a wall mountable dead bolt lock, and a door mountable dead bolt lock which matingly engage in the locked position to secure the sliding door or window shut, is disclosed. The wall mountable dead bolt lock may be moved between an unlocked position and a locked position (where it is received within the housing of the door mounted dead bolt) in an automatic manner by an actuator which is preferably normally biased to extend slightly beyond the door jamb. The actuator may be connected to the dead bolt by a drive assembly which is activated upon movement of the actuator inwardly toward the door jamb, for example by a plunger. In one embodiment, as the actuator moves inwardly, it causes the dead bolt to move outwardly, until it is received within the housing of the door mounted dead bolt. The wall mounted dead bolt includes an aperture at one end for receiving the dead bolt of the door mounted dead bolt therein.