Recurrent posterior shoulder instability is an uncommon condition. It is often unrecognized, leading to incorrect diagnoses, delays in diagnosis, and even missed diagnoses. Posterior instability encompasses a wide spectrum of pathology, ranging from unidirectional posterior subluxation to multidirectional instability to locked posterior dislocations. Nonsurgical treatment of posterior shoulder instability is successful in most cases; however, surgical intervention is indicated when conservative treatment fails. For optimal results, the surgeon must accurately define the pattern of instability and address all soft-tissue and bony injuries present at the time of surgery. Arthroscopic treatment of posterior shoulder instability has increased application, and a variety of techniques has been described to manage posterior glenohumeral instability related to posterior capsulolabral injury.