Abstract: An inner fender liner can be applied against the underside of an exposed fender for protecting the fender from damage by rocks or other objects which may be thrown up against it. The fender liner comprises a relatively thick, but flexible, sheet of plastic material shaped to cover the rear portion of the fender. The liner is bent to conform to the underside of the fender and fit flush thereagainst. At least one peripheral attachment flange, formed by a scored section of the liner, may be used to help hold the liner in place using some of the fasteners normally used to hold the fender on the vehicle.