Abstract: The invention is a trim positioning tool (10) including a trim guide portion (12), a door frame guide (20) and a trim headpiece length marking piece (22). The trim guide portion (12) includes a trim width spacer (14), trim with spacer standoffs (16) and a wall guide (18). The primary usage of the tool (10) is in the position of trim strips and stop strips during the installation of wooden door frames in residential and commerical construction. As so used, the tool (10) performs three separate functions. The tool (10) is used as a measuring device to mark the position for an initial piece of trim. The tool (10) is used to position trim at a proper setback distance and to help hold the trim in place while it is fastened. The tool (10) is also used to position door stop strips.