Temporomandibular joint (TMJ) ankylosis is a severe condition which has a major impact on oral functions and, when affecting children, facial growth. The treatment is surgical and various techniques have been described. Few data are available concerning long-term growth following such treatment in paediatric cases. We present the case of a bilateral TMJ ankylosis following trauma in a 3-year-old child treated with interpositionnal arthroplasty using full-thickness skin graft. The patient was treated rapidly after diagnosis and was followed regularly until completion of growth. A sustained good maximal interincisal opening was obtained along with a satisfying mandibular growth. No complication was recorded, and no additional surgery needed. Excellent clinical results were obtained with a rather minor surgical treatment. The surgical technique used allowed a harmonious facial growth. TMJ ankylosis in children can be managed with good long-term functional and growth results when diagnosed and treated at an early stage.