Posterior shoulder instability is a distinct subcategory of shoulder instability with an incidence higher than previously reported. Pain is typically the primary complaint, with pathology due to repetitive microtrauma being more common that a specific traumatic event. If nonoperative treatment fails, arthroscopic posterior capsulolabral repair has been shown to result in excellent outcomes and return to sport, with American football players having the best outcomes and throwers being slightly less predictable. Risk factors for surgical failure include decreased glenoid bone width, rotator cuff injury, female gender, and the use of less than 3 anchors.