A pickup truck having an extended cab passenger compartment and a pair of front doors disposed on opposite sides of the passenger compartment. A sliding rear door is disposed rearward of one of the pair of front doors. The sliding rear door is supported for sliding movement between a closed position and an open position by an upper track and a pair of lower tracks which are each engaged by a corresponding guide arm which is mounted to the sliding rear door. The upper and lower tracks are mounted so as to be concealed from view when the sliding rear door is in the closed position.