Abstract: A scoring tool that is especially useful for scoring relatively flat and rigid materials, such as siding materials that are used as exterior trim on buildings, includes two scoring members that engage opposite sides of the sheet of material to provide a straight score line along the material. The scoring members are supported on mounting members that are adjustably moveable relative to a body portion. The body portion includes a groove that receives an edge of the material as the tool is moved along the length of the material. The scoring members engage opposite sides of the material to provide a straight score line that then provides the ability to manually remove the desired portion of the material.