Abstract: A clamping bookend which can be securely mounted at selected locations along a shelf includes a body member containing a slot for receiving the shelf, a clamping member pivotally connected with the body member which serves to clamp the bookend to the shelf when pivoted to an upright position, and a stop member or partition connected with the top of the clamping member for retaining objects, such as books, on the shelf. A flex member which serves to increase the clamping force on the shelf as the load applied to the clamping member increases is also disclosed. The flex member is provided at the lower end of the clamping member and extends into the slot receiving the shelf.