A motor vehicle door lock includes a locking mechanism having a rotary latch, a pawl, and an actuating lever mechanism having at least one coupling lever rotatable about an axis and a mass inertia element rotatable about an additional axis spaced apart from the axis of the coupling lever to guide the coupling lever, at least in the event of an accident. The coupling lever in its “engaged” position connects the actuating lever mechanism mechanically with the locking mechanism and in its “disengaged” position ensures that the actuating lever mechanism is locked and/or separated from the locking mechanism. The mass inertia element has a guide contour for the coupling lever that interacts with a contact contour of the coupling lever so that the guide contour and/or contact contour is configured so that a force exerted upon it runs essentially tangentially to the diameter of the associated axis.