An awning mechanism for a recreational vehicle having a slider includes a box awning having a frame and a roller disposed therein with an awning rolled about the roller and extendable therefrom. The awning includes a leading edge and a bracket is provided for mounting the frame to a stationary wall of the recreational vehicle. A header attachable to the slider beneath the frame is provided with the bracket and the header having a generally coplanar relationship with the slide out in a fully retracted position. Linkage is provided which interconnects the header and the leading edge and includes structure enabling shortening of the linkage as the header passes beneath the leading edge on the roller.