A ring binder has an elongate body and rings. Each ring includes ring members moveable between open and closed positions. The body and rings are made of one or more moldable polymeric materials. The binder suitably includes a retaining system operable to hold the ring members in the closed position. The retaining system has interlocking formations adjacent ends of the ring members that are moveable between a retaining position in which the retaining system holds the first and second ring members in the closed position and a non-retaining position. The ring members and body can suitably be formed together as one piece from a moldable polymeric material.