Lateral epicondylitis, often called “tennis elbow,” is a musculoskeletal condition characterized by pain around the lateral elbow and adjacent forearm with resisted wrist extension or passive terminal wrist flexion with the elbow in full extension, plus tenderness over and/or just distal to the lateral epicondyle. The name is a misnomer because the pathology is neither inflammatory nor located in the lateral epicondyle but rather represents a chronic tendinosis with disorganized tissue and neovessels of the tendon originating from the extensor carpi radialis brevis muscle and less commonly the extensor digitorum communis muscle, which originate on the lateral epicondyle. Clinical assessment involves understanding the chronology, precipitating activities, current symptoms, and interference with activities of daily living. Physical examination is performed bilaterally and includes palpitation provocative testing, measuring elbow and wrist motions, and neurological evaluation. Many treatments have been proposed, but little quality evidence supports any specific approach; more than 90% of cases are managed nonoperatively. Severe cases that have failed at least months of nonoperative management may warrant surgical assessment, but studies of surgical results for treatment of lateral epicondylitis are limited. Impairment rating may be necessary in a minority of cases and involves using the AMA Guides to the Evaluation of Permanent Impairment (AMA Guides), Sixth Edition, based on diagnosis-based impairment and using Table 15-4, Elbow Regional Grid: Upper Extremity Impairments.