Purpose <p>Anterior shoulder instability (ASI) is a common shoulder condition that primarily affects adolescents and young adults. In older adults this represents a distinct condition with a distinct pathomechanism and complication profile. This review synthesizes the literature on ASI in patients 40 years or older, focusing on injury characteristics, treatment modalities, and clinical outcomes.</p> Methods <p>Three databases (PubMed, MEDLINE, Embase) were searched on October 18, 2025. Primary studies investigating operative or non-operative management of ASI in patients with onset of instability at ≥ 40 years old were included. Methodological quality was assessed using MINORS criteria. Data were collated utilizing descriptive statistics.</p> Results <p>Ten studies were included with 541 patients, of which 315 were non-operative and 226 were operative. The most common concomitant injuries included rotator cuff tears (<i>n</i> = 219 of 409, 53.5%), Hills-Sachs lesions (<i>n</i> = 208 of 445, 46.7%), and glenoid bone defects (<i>n</i> = 20 of 249, 8.0%). The most common operative procedures were rotator cuff repair (80.5%, <i>n</i> = 182), Bankart repair (12.8%, <i>n</i> = 29), and reverse shoulder arthroplasty (4.4%, <i>n</i> = 10). Recurrent instability occurred in 5.5% of operative patients (<i>n</i> = 21 of 380) and 15.0% of non-operative patients (23 of 153) among studies reporting rates. Both non-operative and operative management yielded favourable outcomes, with low recurrence and complication rates, and satisfactory range of motion.</p> Conclusions <p>ASI in patients ≥ 40 years old is commonly associated with concomitant injuries and can be managed operatively or non-operatively depending on injuries and instability severity. Further prospective, comparative studies using standardized outcomes are needed to better define optimal management in this population.</p> Level of Evidence <p>IV, systematic review.</p>