The study of gambling disorder is important from both clinical and research perspectives. Gambling disorder is a common disorder that is associated with significant morbidity (decreased self-esteem, comorbid substance use disorders, financial and legal difficulties, stress on relationships and families, and suicidality). Over the past 16 years, our understanding of the phenomenology, epidemiology, neurobiology, psychology, and treatment of this disorder has increased. Unfortunately, although many clinicians encounter individuals with gambling disorder (elevated rates of gambling disorder are observed in patients with other mental health disorders), clinicians often do not diagnose gambling disorder and are frequently unaware of the treatment options for the disorder.