Disclosed herein is a panelboard guard assembly configured to restrict access to a panelboard having a cover and a door defined therein, the cover having first and second side edges. The panelboard guard assembly includes overlapping members that are, at least in some implementations, mutually coupled to each other. The panelboard guard assembly further includes an adjustment mechanism that extends between and couples the members together, the adjustment mechanism facilitating adjustment of the distance between the outer ends of the members.