Abstract: A sandwich wall system panel comprising an insulating core (18), a first metal skin (14) adhered to one face of the core, a second metal skin (16) adhered to the opposite face of the core, a rim portion (36,38) associated with and extending along one longitudinal edge of each of said first and second metal skins, said rim portions facing one another, the free ends of said rims portions extending in parallel spaced relation to one another, to define a central joining tongue flanked by a pair of channels (100,102) and extending from the longitudinal edge of the panel, a pair of spaced parallel legs (76,78) formed by marginal portions of said first and second skins (14,16) and projecting beyond the core (18) at the opposite longitudinal edge of the panel, said legs (76,78) being spaced to form a groove to receive the tongue of an adjacent, similar panel, the legs then being accommodated within the channels of the adjacent panel, and at least one rigid connector (62), inserted between said rim portions (36,38) co