A structure for mounting a high-mounted stop lamp. An upper housing and a lower housing are not provided. A stop lamp having a reflector and a lens is placed in a space defined by a cover part of a tailgate trim which is formed to have a configuration for receiving the stop lamp therein. A pair of mounting sections protrudes from left and right portions of a rear wall of the reflector. By the medium of the pair of mounting sections, the reflector is locked by bolts to a tailgate inner panel which is positioned above the reflector and is coupled by clips to the cover part of the tailgate trim which is positioned below the reflector.
