Treatment of skeletal Class III patients at younger age is highly unpredictable. The patient may respond well to the treatment or may show excessive mandibular growth during growth spurt which may require orthognathic surgery later on. If not treated at earlier stages of life, the condition may worsen with time. This case report will present the comprehensive orthodontic management of a 9-year-old prepubertal girl in late mixed dentition with prognathic mandible. Chin cup therapy was started and continued for 3 years. After chin cup therapy, maxillary and mandibular dentition were bonded with standard edgewise appliance. After leveling and alignment, Class III elastics were started. Fixed orthodontic treatment was completed in 3 years. At the end, good Class I molar and canine relationship with normal overjet and overbite were achieved. The total treatment time of orthopedic and orthodontic correction was 6 years, 2 months. The patient revealed the same Class I molar and canine relationship after 6 years of treatment. Redirection of mandibular growth pattern from hyperdivergent to normodivergent advocates the use of chin cup as a viable treatment regimen for the management of prognathic mandible in prepubertal patients.