Comes assembled. Even with proper measuring and insertion of a molly (if not in a stud), one of the hanging eyelets required tweaking. I had to unscrew it and flip it over because it was dented inwards preventing the screw to latch in properly. As a result of that change, even though my measurements and install was level to the ground, the shelf has an uneven appearance and peak/gap. But, whatever, not the end of the world! It meets my needs.One last thing. the usable shelf depth is NOT 4” (it’sSee full review