Abstract: A stackable archive container (10) is formed from a cardboard sheet, and comprises, when in the stacked state, two side walls (14, 16), a top wall (18), a bottom wall (20) and a rear wall (12), with a closure flap (22) being hinged to the top or bottom wall. Reinforcing bars (41; 58; 64) are provided on the vertical side edges of the side walls and/or the back wall. The bars are typically extruded from aluminum, and have a U-shaped profile that extends the length of the side edges of the side and/or back walls, and embraces the side edges in a snug push fit. The reinforcing bars may have a U-, H- and/or W-configuration. The profiles enable the stacking height of the containers to be increased, and also serve to interconnect adjacent containers.