A 17-year-old woman was admitted to our institution because of tracheal stenosis. She had undergone tracheostomy after a traffic accident, but the stenosis had persisted. Chest computed tomography showed retrosternal dislocation of the right sternoclavicular joint and compression of the trachea by the medial head of the right clavicle. To relieve the tracheal compression, 3 cm of the medial head of the clavicle was resected. The dyspnea disappeared completely, allowing closure of the tracheostomy. Posterior dislocation of the sternoclavicular joint and tracheal stenosis due to compression by the dislocated clavicle is rare.