A 9-year-old boy presented with an anterior crossbite on tooth 21 and an upper shift to the right. Model analysis showed there was more tooth material in the upper arch than the lower arch. Cephalometric analysis found retroclination of the lower incisors. The treatment plan is to use a Hawley's appliance with a Z-spring on tooth 21 to correct the crossbite of the upper left lateral incisor.