Abstract: An extendable shelf assembly is removably mounted on the slotted uprights of a display stand and comprises a shelf mounted on a shelf support, a shelf extender attached to said shelf and the shelf support and operable so that the shelf can be extended or retracted. A manually operable locking device permits the shelf to be extended or retracted and moved from one position to another when the locking device is released, the locking device retaining the shelf in its selected position when engaged. An angularly adjustable shelf support assembly which comprises a first mounting member with structure thereon for releasably attaching the member to a slotted upright and a second mounting member for attachment to the shelf to take the load thereof.