A collapsible dunnage box is provided that includes a box base and first and second opposed base sidewalls attached to the box base on opposing sides of the box. First and second opposed top sidewalls are pivotally attached to the top edge of respective ones of the base sidewalls. First and second opposed top endwalls are provided to form a box enclosure. The base endwalls are pivotally-mounted to the top endwalls and are moveable between a lowered, vertical deployed position enclosing respective ends of the box and a raised, horizontal stowed position to contain and store dunnage positioned in an upper portion of the box.