Abstract: An outlet box assembly in which the position of the box is slidably adjustable along an arm of the bracket which mounts the box to the wall. Slidably supported to one of the plurality of walls defining the outlet box is a bracket which has a support arm extending substantially parallel to the side wall of the box and a mounting arm extending substantially perpendicular thereto. The bracket support arm has a plurality of openings to engage the outlet box and the mounting arm secures the box to the wall in which the assembly is to be installed. An engagement tab extends from the side wall of the box and engages with one of the openings in the bracket support arm, thereby retaining the outlet box in a position. A flexible element coupled to the engagement tab biases the engagement tab to engage an opening in the support arm.