Abstract: A three-sided drilling template for a door is provided that is formed from a rigid material. The first and second sides of the template are parallel and contact opposite sides of the door. The third side of the template, orthogonal to and bridging the span between the first and second sides of the template, contacts the edge of the door. A plurality of through guide holes are located in each side of the template and mark the centers of mounting holes for the mounting of operating hardware such as door locks and knobs. Markings on the template indicate the specific purpose of each through guide hole, and marked circles concentric with the through guide holes indicate the correct size of the mounting holes. A rectangular extension on the interior surface of the third side fits into a lock face recess previously formed or pre-machined in the edge of the door for accurate alignment of the template to the door.