Obesity is a complex condition associated with a host of medical disorders. A common assumption is that obesity must also be related to psychological and emotional complications. Research on the psychosocial aspects of obesity has grown more sophisticated over the years, from purely theoretical papers to cross-sectional comparisons of people with and without obesity to prospective investigations of the temporal sequence of obesity and mood disturbance. These studies have shown that obesity, by itself, does not appear to be systematically associated with psychopathological outcomes. Certain obese individuals, however, are at greater risk of psychiatric disorder, especially depression. The present paper reviews the research findings and presents their clinical implications. Chiefly, treatment providers should not assume that a depressed or otherwise disturbed obese person needs only to lose weight in order to return to psychological health. Significant mood disturbances should be treated equally aggressively, regardless of a patient's weight status.