Abstract: An integrally molded, one-piece, plastic shelf unit which can be mounted directly on a surface either singly, or adjacent similar units, without the need for separate mounting structures such as brackets, and which is nestable for convenient shipment and storage is disclosed. It has a flat horizontal support wall, an integral front wall which extends downwardly from the front edge of the support wall, integral sidewalls which extend downwardly from the side edges of the support wall, and an integral external mounting flange wall which extends outwardly from the rear edges of the support wall and the sidewalls to provide an unobstructed rear opening in which a similar unit may be nested.