Abstract: Disclosed is a support structure for holding house plants or the like in position to receive optimal sunlight at a window. The structure comprises a pair of elongate support members which rest on the window sill and extend upwardly and inwardly into the room. C-hooks attached to the base of the support members pass over the nosing of the window trim and prevent slippage; cables extend between eyes screwed into the window track and the top of the support members. The support members hold one or more shelves, each of which comprise a plurality of parallel rails extending horizontally between rail holding brackets. The brackets define holes dimensioned to interfit with the support members and to slide therealong. When a load is placed on the rails, vertical slippage of the shelves is prevented by a gripping action exerted by the rail holding brackets on the support members.