A pot light assembly includes a rail and a pot light housing for housing a pot light. The rail has end portions for resting on upwardly facing surfaces of a pair of ceiling joists and a central portion between the end portions. The central portion is secured to a side wall at a top portion of the housing for supporting the housing between the ceiling joists. The pot light assembly further includes a pair of fastening brackets for securing the rail to the ceiling joists. Each bracket has a fastening plate positioned below the rail. The fastening plates have respective fastening holes through which a fastener can be secured to respective ceiling joists to fasten the fastening plates to the ceiling joists.