The long-term results of classic arthroscopic Bankart repair remain suboptimal, with recurrence rates of up to 30% after a decade. To address this, augmentation techniques have been introduced to improve shoulder stability outcomes. Arthroscopic subscapularis augmentation (ASA) represents one such additive procedure, using the subscapularis tendon to recentralize the humeral head and enhance anterior stability during external rotation. ASA is performed in conjunction with standard Bankart repair and can also be combined with bony procedures, such as the Eden-Hybinette, in cases of capsular insufficiency or subcritical bone loss. The technique is straightforward, reproducible, and associated with a low learning curve, as the surgical skills required are comparable to those of a conventional Bankart repair. Early- to mid-term results demonstrate excellent functional outcomes, low recurrence rates, and minimal clinically relevant restrictions in external rotation, although long-term data are still limited. This chapter outlines the indications, surgical steps, technical pearls, pitfalls, and reported outcomes of ASA, establishing it as a safe and effective alternative among modern arthroscopic strategies for recurrent anterior shoulder instability.