An adjustable width headache rack capable of accommodating the widths of multiple pick-up truck vehicles and mounting thereon including a frame member having an upper load bar and a lower cross bar each extending between two upright members spaced a distance from one another. Leg members extend from each upright member in a rearward direction on top of bed rails of the pick-up truck. The leg members have a sleeve portion which slidingly engages the lower cross bar thereby enabling width adjustment. Screen members are interchangeable within the truck rack frame.