This review summarizes the role of cognitive-behavior therapy (CBT) in obesity treatment. Although not a specific intervention per se, CBT is the systematic application of principles of social cognitive theory to modify behaviors that are thought to contribute to or maintain obesity. Most forms of CBT include the use of five strategies: self-monitoring and goal setting; stimulus control for the modification of eating style, activity, and related habits; cognitive restructuring techniques that focus on challenging and modifying unrealistic or maladaptive thoughts or expectations; stress management; and social support. The use of these strategies in comprehensive obesity programs has been helpful in improving short-term weight losses, but long-term success remains elusive, even though these strategies are predictors of long-term weight loss maintenance. Given that obesity is a chronic condition, not unlike hypertension or diabetes, CBT interventions will need to focus on broader treatment outcomes, such as improved metabolic profiles, quality of life, psychological functioning, and physical fitness. In addition, new methods for delivering CBT interventions should be explored, including home-based programs and combination with adjunctive pharmacotherapy delivered in primary care centers.