Shoulder stiffness is a common but poorly understood disorder of the glenohumeral joint. Many terms are used to describe a stiff shoulder, including frozen shoulder and adhesive capsulitis. This article reviews the terminology, classification, diagnostic options, and management options of shoulder stiffness. Conservative measures,emphasizing a four-quadrant stretching program, typically produce effective treatment outcomes. Operative interventions, which may be required for the small percentage of patients who fail conservative therapy, are also presented.