Patient-reported outcome scales determine response to treatment. The minimal clinically important difference of these scales is a measure of responsiveness: the smallest change in a score associated with a clinically important change to the patient. This study sought to summarize the literature on minimal clinically important difference for the most commonly reported shoulder outcome scales. A literature search of PubMed and EMBASE databases identified 193 citations, 27 of which met the inclusion/exclusion criteria. For rotator cuff tears, a minimal clinically important difference range of 9-26.9 was reported for American Shoulder and Elbow Surgeons, 8 or 10 for Constant, and 282.6-588.7 for the Western Ontario Rotator Cuff Index. For patients who underwent arthroplasty, a minimal clinically important difference range of 6.3-20.9 was reported for American Shoulder and Elbow Surgeons, 5.7-9.4 for Constant, and 14.1-20.6 for the Shoulder Pain and Disability Index. For proximal humeral fractures, a minimal clinically important difference range of 5.4-11.6 was reported for Constant and 8.1-13.0 for Disability of the Arm, Shoulder, and Hand. A wide range of minimal clinically important difference values was reported for each patient population and instrument. In the future, a uniform outcome instrument and minimal clinically important difference will be useful to measure clinically meaningful change across practices and the spectrum of shoulder diagnoses.