Abstract: A system for preventing a child from voluntarily or accidentally leaving the chair in which he or she is seated. The system provides a partial enclosure of the child's upper legs and lower torso, the enclosure being contoured to the general shape of these parts of a seated child. Also provided are a tenon sliding in a mortise and a pawl which engages ratchet teeth to permit adjusting the system for the size of the child and for locking the components of the system together during use.