To provide a top-railed sliding door which does not undergo rolling when moved, is proof against flapping in a closed state even if strong wind blows, and has its sill arranged so as not to hinder passage of passengers or wheelchairs.

The top-railed sliding door is formed of the sill 1 and a door 2. The sill 1 has a protruding rail 3. The door includes a windage stopper 4 at a lower portion thereof, which has a sash roller 5 traveling on the rail 3, and protrusions 6 formed inside and outside the sash roller, in a manner protruding downward from the sash roller 5 to be located inside and outside the rail 3, respectively. The windage stopper 4 is energized downward by a spring 7. The sill 1 has recesses 8 formed therein, at a location below the windage stopper 4 when the door 2 is closed, for storing therein the protrusions 6 of the windage stopper, respectively, and the rail 3 has its portions adjacent to the recesses 8 inclined downward toward the recesses 8, such that the windage 4 can move downward when the door 2 is closed.