Rotator cuff tears are a common cause for shoulder dysfunction and can have significant impact on the individual, with decreased function during activities of daily living, ability to work. Rotator cuff tears are managed with surgical repair and rehabilitation or conservatively with physical therapy. Electromyography (EMG) has been used to objectively measure shoulder muscle activation during both isometric and functional tasks to determine differences between participants with symptomatic and asymptomatic rotator cuff tears compared with healthy control subjects. The identification of different shoulder muscle activity patterns could enhance our understanding of the consequences of rotator cuff tears and help to guide more targeted conservative management and postoperative rehabilitation. The purpose of this review was to summarize current evidence by comparing EMG activity of patients with symptomatic rotator cuff tears with healthy controls or to individuals with asymptomatic rotator cuff tears.