In one embodiment, a lighting fixture adapter includes a sliding rail structure configured to slidably receive an insert and a mounting slot positioned below the sliding rail structure and configured with one or more mounting holes at a bottom of the mounting slot. The insert may be configured to be secured to a mounting position. The one or more mounting holes may be configured to receive one or more mounting features to secure a lighting device to the lighting fixture adapter. A position of the insert in the sliding rail structure is adjustable within a length range of the sliding rail structure.