The Inaccessible Island Rail (Atlantisia rogersi) is a small bird of the rail family, Rallidae. It is the only species in its genus. It is found only on Inaccessible Island in the Tristan Archipelago, and is notable for being the smallest extant flightless bird in the world. Unlike many other islands, Inaccessible Island has remained free from introduced predators, allowing this species to flourish while many other flightless birds, including the even smaller Stephens Island Wren, have perished.