Abstract: A portable, lightweight security lock for doors comprising an elongate movable abutment member and an elongate catch member pivotally secured thereto. The abutment member has a laterally extending abutment portion for disposition in proximity with the door surface when such door is closed; the elongate catch member has a laterally extending catch portion which is insertable into the latch socket of a door jam. In a preferred embodiment the elongate movable abutment member includes a resilient pad on its forward surface, this to accommodate tolerances and deviations thereof in actual casement and lock installations. The elongate movable abutment member and elongate catch member are provided with inter-cooperating dog and teeth means which inter-engage selectively, depending upon the door installation involved, this so that need not be present pivotal movement between the two members when the movable abutment member is to be released from engagement with the door.