A sliding door structure for a vehicle having a continuous door opening consisting of a side opening formed in a side body panel and a roof opening formed un a roof panel comprises a generally reverse L-shaped sliding door having a side portion in conformity with the side opening and a roof portion in conformity with the roof opening and a door guide structure operative to guide the sliding door in a lengthwise direction between a closed position and an open position, the door guide structure consisting of an upper guide rail for supporting a middle portion of the sliding door and a lower base guide rail slidably support a lower end of the sliding door.
