Abstract: A knock-down bed frame assembly formed from extruded plastic components. The knock-down bed frame assembly includes a frame having a pair of side rails and a pair of end rails joined together to define the rectangular peripheral edge of the bed frame. Both the side rails and the end rails are formed from sections of extruded plastic. The side rails are each formed from at least a pair of side boards connected to each other by a connector bracket, also formed from plastic. Each of the side rails includes a support section having a mounting slot that receives an end cap formed on each of a plurality of top panels. The top panels are mountable between the side rails to provide a support surface for a mattress. The entire knock-down bed frame can be disassembled into individual components that can be contained within a conventional shipping container.