A door security device (1) consisting of a substantially trapezoidal plate (4) residing parallel to the plane of the door and an integrally formed lip (6) which is permanently affixed to door frame structural member (2). A door strike reinforcement tube (10) extends perpendicularly from plate (4) and is aligned with door lock striker (25) such that any force applied to the door (15) is resisted by the entire plate reinforcing device. A plurality of strike plate reinforcement extensions (10a) may also be used with multiple lock mechanisms.