BACKGROUND: Congenital muscular torticollis (CMT) is a common pediatric abnormality involving sternocleidomastoid (SCM) muscle. The pathogenesis of CMT has yet to be elucidated, but intrauterine abnormalities seem to be a plausible explanation. This condition, if left untreated, may result in craniofacial asymmetry, neck pain, and limited neck movement. We reported a case of an 11-year-old girl with CMT, which symptoms were first noticed at the age of 4, but were neglected by her parents, the patient was then treated with a complete unipolar SCM release. CASE PRESENTATION: An 11-year-old girl presented with neck stiffness and limited head movement, first noticed at the age of 4, but was neglected. These symptoms worsened within the last few weeks. Physical examination revealed tension and tightness in the left SCM muscle. The patient then underwent complete unipolar release of SCM muscle and proceeded to aggressive physiotherapy for 3 months and put to rigid collar neck for the next 3 weeks. Follow-up was done in the fourth week and a full range of motion (ROM) of the neck was achieved. DISCUSSION: The timing of surgery could yield a good result if performed within 1–4 years of age. However, another literature stated that surgical intervention in the older patient with CMT could still result in better outcomes. Therefore, in this case, we proceeded to perform a complete unipolar release on the left SCM muscle. Post-operative results were satisfying, with significant improvement in neck ROM. CONCLUSION: Surgical approach in adolescents with CMT may still carry a favorable outcome, in terms of better ROM and neck motion. Subsequent physiotherapy and brace placement were crucial to maintaining the results of the surgery.