Abstract: A nestable frame for planar air filters or other screen-like planar structures. The nestable frame provides all of the following desirable properties at once: 1. Simple manufacturing and assembly process, 2. Simple design, 3. Enhanced structural rigidity, 4. Significant space-savings during storage and transport, and 5. Simple handling. The filter frame comprises an upper and a lower frame portion with a first leg each, where the peripheral edge of the filter media is clampingly engaged between the first leg of the upper frame portion and the first leg of the lower frame portion. From the first leg, both frame portions extend outwardly with a second leg at an obtuse angle. The frame portions are connected at the outer ends of their second legs with a connecting leg. Alternative embodiments contain straight connection legs at different angles, curved connection legs or a multitude of connection legs, oriented to the outside of the frame or collapsed inwardly into the frame, for various purposes.