Abstract: An extendible truck bed storage assembly for accessing contents of a truck bed from a rear thereof includes a box, which is sized so that the box is removably insertable into the bed with opposed sides of the box being positioned proximate to the tire wells. The box has a top and a front, which are open. A ridge is engaged to a bottom of the box and positioned therein adjacent to the front. A tray is positioned in the box and is selectively extendible from the box through the front. A set of slats is engaged to a lower face of the tray with each slat being perpendicular to opposed edges of the tray. A user can lift and pull on the forward end of the tray to selectively extend is to access articles positioned thereon. The slats engage the ridge to prevent the tray from sliding until lifted.