Abstract: A door jamb support includes an L-shaped reinforcing plate having a recessed portion with an opening therethrough positioned to be in alignment with a door latch on a door, a strike plate positionable within the recessed portion having an opening therethrough in alignment with the opening in the reinforcing support plate, an adjustment mechanism for adjusting the position of the strike plate on the support plate to vary the location of the strike plate opening with respect to the support plate opening, the fasteners for mounting the strike plate on the support plate. The adjustment mechanism includes a series of spaced projections on the strike plate above and below the strike plate opening and a corresponding series of spaced indentations on the support plate above and below the support plate opening. The adjustment feature enables the reinforcing support plate to accommodate variances in the design of and in the position of door handle latches in doors.