The specification discloses a collapsible pallet box or container composed of a pallet platform and four upright panels connected together at the corner edges by flexible material to form a polygon expandable to a rectangle or collapsible to a flattened parallelogram. The bottom of the polygon panels are removably attached to the pallet. The tops of the panels have a stabilizing grid with interconnected compression elements between the panels to stabilize the panel tops in the expanded rectangular configuration, and interconnectable, releasable hook and loop fasteners on the grid and on the polygon upper end, at the corners of the grid and recessed into the corners of the polygon, to keep the grid secured to the polygon and thereby keep the polygon locked to the pallet.