Abstract: A sliding door locking device, the sliding door having a frame that engages with a door jamb or a second sliding door frame. The device may include a locking body connected to the door jamb or second sliding door frame. The locking body may be linear alignment with a path of the first sliding door and the first sliding door frame may be configured to receive the locking body. A latching body may be connected to the first sliding door frame and operable to engage with the locking body. First and second controllers may be connected to the first door frame and operable to control the latching body towards and away the locking body. Bypass means may be connected to the first sliding door frame and in mechanical communication with the second controller and with the latching body. Authentication means may be in communication with the bypass means, wherein the bypass means renders the second controller inoperable until the authentication means verifies a user.