A drywall scribing and scoring tool for a typical wallboard is provided in which a knife holding unit and scribe units can be adjusted along a scale on an elongated arm of a T-square member. When the short head portion of the T-square member is slid along one edge of the wall board by a person the tool will cut a score into the wall board for breaking to a predetermined size and mark center lines for wall stud nailing locations simultaneously upon the wall board allowing easy installation of the wall board to the wall studs.
