Thoracic outlet syndrome comprises a group of disorders that result in compression of the brachial plexus and subclavian vessels exiting the thoracic outlet. Symptoms include pain, paresthesia, pallor, and weakness depending upon the compromised structures. While consensus in diagnostic criteria has not yet been established, a thorough patient history, physical exam, and appropriate imaging studies are helpful in diagnosis. General first-line therapy for thoracic outlet syndrome is a conservative treatment, and may include physical therapy, lifestyle modifications, NSAIDs, and injection therapy of botulinum toxin A or steroids. Patients who have failed conservative therapy are considered for surgical decompression. This article aims to review the epidemiology, etiology, relevant anatomy, clinical presentations, diagnosis, and management of thoracic outlet syndrome.