Glenohumeral dysplasia can occur in brachial plexus birth palsy due to an imbalance of muscle forces. Most commonly this occurs in C5-C6 injuries where the shoulder external rotators are weak compared with the shoulder internal rotators. Treatment of the dysplasia with open reduction of the glenohumeral joint in combination with rebalancing the muscles can improve the development of the joint. Furthermore, the tendon transfer can improve shoulder function by decreasing the internal rotation forces about the shoulder while increasing the external rotation forces. This paper describes the indications, contraindications, and technique of performing an open glenohumeral joint reduction and latissimus dorsi and teres major tendon transfers for brachial plexus birth palsy.