Langen Beck disease, a rare idiopathic disorder, causes enlarged coronoid processes of the mandible, leading to restricted oral opening and deteriorating health. This paper presents a 10-year-old boy’s case with bilateral hyperplasia of the coronoid processes (HCP), diagnosed using cranial computed tomography, severely limiting oral opening to 18 mm. Treatment involved early intraoral coronoidectomy followed by physiotherapy, yielding immediate oral opening improvement without recurrence after 1 year. Surgical timing should consider age, disease severity, and progression risk. While HCP etiology lacks conclusive evidence, genetic mutations may explain cases without identifiable causes. This case underscores the significance of timely intervention for HCP to alleviate symptoms and improve long-term outcomes, emphasizing individualized treatment strategies.