Abstract: A lock for use with a garage door having an automatic garage door opener attached thereto includes a housing which attaches to the garage door. A bracket attaches to the inside of the garage and is positioned such that the housing and the bracket are in close proximity to each other when the garage door is closed. An element is movably mounted on the housing to move between a locked and unlocked position. The automatic garage door opener attaches to the element and is capable of moving both the element between its locked and unlocked positions and moving the garage door via motion imparted to the door via the housing and the element. When the garage door is closed and the element is moved from its unlocked to its locked position the garage door is securely locked against being opened by an outside influence.