Background: Flexion of one elbow is essential to enable children with arthrogryposis to achieve independent function such as self-feeding and self-care of the face and hair. We analyzed the outcomes of posterior elbow capsulotomy with triceps lengthening for the treatment of elbow extension contractures in a series of children with arthrogryposis multiplex congenita. Methods: The medical records of all children with arthrogryposis who had been followed for a minimum of two years after treatment with elbow capsulotomy and triceps lengthening were retrospectively reviewed. The postoperative range of motion and ability to reach the mouth were compared with the preoperative status. Results: Posterior capsulotomy with triceps lengthening was performed in twenty-nine elbows of twenty-three children with an average age of thirty-five months (range, seven months to thirteen years). The average duration of follow-up was 5.4 years. The arc of motion of all twenty-nine elbows improved from an average of 32° (range, 0° to 75°) preoperatively to an average of 66° (range, 10° to 125°) at the time of final follow-up. All children were able to reach the mouth using passive assistance (e.g., table-push, trunk-sway, and cross-arm techniques), and twenty-two children were able to feed themselves independently. No child underwent subsequent tendon transfer surgery. Conclusions: Elbow capsulotomy with triceps lengthening successfully increases passive elbow flexion and the arc of elbow motion of children with arthrogryposis, enabling hand-to-mouth activities. In contrast to studies in which tendon transfer surgery was used to increase elbow flexion, none of the children in this series underwent subsequent tendon transfer surgery. Level of Evidence: Therapeutic Level IV. See Instructions to Authors for a complete description of levels of evidence.