Abstract: A box divider used in conjunction with boxes having differing side wall thicknesses includes a vertical partition which carries locking assemblies on its opposing sides. The locking assemblies operationally engage a pair of mounting pins horizontally extending within the interior of the box. The locking assemblies are vertically adjustable and abuttingly contact ribs formed along the body of the mounting pins. The bottom of the partition includes a base having a series of spikes depending therefrom which penetrate the bottom surface of the box to thereby hold the same securely in place. The back surfaces of the locking assemblies are formed having a high coefficient of friction, to thereby frictionally engaging the interior surface of the box. The locking assemblies each preferably include a guide having a vertical channel onto which is slidably mounted a wedge having a channel in registration with the channel formed in the guide.