Glenoid bone loss is commonly associated with recurrent shoulder instability. Failure to recognize and appropriately address it can lead to poor outcomes. Numerous studies have found anterior-inferior glenoid bone loss in the setting of recurrent anterior instability. Though much less common, posterior shoulder instability can be seen in the setting of acute trauma, epilepsy, electrocution, and alcoholism. Heightened awareness has led to recognition in collision athletes as well. Posterior glenoid bone loss must be addressed in a similar fashion to anterior glenoid bone loss to prevent recurrent instability. Open bone augmentation procedures have been described with successful results. In this technical note, we describe an arthroscopic technique using fresh distal tibial allograft for posterior glenoid augmentation. In addition, a current review regarding the diagnosis and management of recurrent posterior shoulder instability is provided.