OBJECTIVE To determine the effects of a brief single component of the graded motor imagery (GMI) sequence (mirror therapy) on active range of motion (AROM), pain, fear avoidance, and pain catastrophization in patients with shoulder pain. DESIGN Single-blind case series. SETTING Three outpatient physical therapy clinics. PARTICIPANTS Patients with shoulder pain and limited AROM (N=69). INTERVENTION Patients moved their unaffected shoulder through comfortable AROM in front of a mirror so that it appeared that they were moving their affected shoulder. MAIN OUTCOME MEASURES We measured pain, pain catastrophization, fear avoidance, and AROM in 69 consecutive patients with shoulder pain and limited AROM before and immediately after mirror therapy. RESULTS There were significant differences in self-reported pain (P=.014), pain catastrophization (P<.001), and the Tampa Scale of Kinesiophobia (P=.012) immediately after mirror therapy; however, the means did not meet or exceed the minimal detectable change (MDC) for each outcome measure. There was a significant increase (mean, 14.5°) in affected shoulder flexion AROM immediately postmirror therapy (P<.001), which exceeded the MDC of 8°. CONCLUSIONS A brief mirror therapy intervention can result in statistically significant improvements in pain, pain catastrophization, fear avoidance, and shoulder flexion AROM in patients presenting with shoulder pain with limited AROM. The immediate changes may allow a quicker transition to multimodal treatment, including manual therapy and exercise in these patients. Further studies, including randomized controlled trials, are needed to investigate these findings and determine longer-term effects.