BACKGROUND: Although reverse total shoulder arthroplasty (RTSA) has been successful in improving pain and function in most patients, some patients fail to improve clinically. The present study used a large registry of RTSA patients to evaluate associations between patient-related factors and poor postoperative improvement after RTSA. MATERIALS AND METHODS: A prospectively collected shoulder arthroplasty registry was queried for consecutive patients who underwent RTSA from 2007 to 2013. Patients with baseline and minimum 2-year postoperative American Shoulder and Elbow Surgeons (ASES) scores were included. Poor postoperative improvement was defined as a change in the ASES of less than 12 points. Multivariate logistic regression analysis was used to identify independent risk factors. RESULTS: A total of 150 patients met inclusion and exclusion criteria. Logistic regression revealed that male sex (adjusted odds ratio [OR], 7.9; P = .004), presence of an intact rotator cuff at the time of surgery (adjusted OR, 4.8; P = .025), depression (adjusted OR, 11.2; P = .005), a higher baseline ASES score (P < .001), and higher total number of medical comorbidities (P = .035) were associated with poor postoperative improvement after RTSA. CONCLUSIONS: Surrogates for better preoperative function after RTSA, such as a higher baseline ASES score and intact rotator cuff at the time of surgery, correlated with poor postoperative improvement. In addition, male sex, depression, and total number of medical comorbidities also correlated with poor postoperative improvement. Interestingly, factors such as patient age and indication for surgery were not found to correlate with poor improvement after RTSA.