Abstract: A stage system and apparatus for construction of flat stages, choral risers, and the like which utilizes a basic structural flat rectangular panel module with an edge of extruded material having a re-entrant groove on the outer surface and upper and lower sockets on each side of each corner of the panel to receive support legs fashioned to be received in the bottom sockets. Railing stanchions are provided to seat in the top sockets. In the vertically spaced and overlapping choral risers, the top sockets serve to locate the overlap and mechanically lock the panels in an overlap position. Inserts received in the re-entrant groove interengage with the re-entrant groove of an adjacent panel to provide lateral and vertical stability to adjacent panels.Special leg brackets are provided to engage the bottom sockets of two to four adjacent module panels to provide vertical support and lateral retention. Leg assemblies can be formed as a folding frame to facilitate shipping and storage.