Narcissistic personality disorder (NPD) is a personality disorder characterized by a life-long pattern of exaggerated feelings of self-importance, an excessive need for admiration, a diminished ability or unwillingness to empathize with others' feelings, and interpersonally exploitative behavior. Narcissistic personality disorder is one of the sub-types of the broader category known as personality disorders. It is often comorbid with other mental disorders and associated with significant functional impairment and psychosocial disability.

Personality disorders are a class of mental disorders characterized by enduring and inflexible maladaptive patterns of behavior, cognition, and inner experience, exhibited across many contexts and deviating from those accepted by any culture. These patterns develop by early adulthood, and are associated with significant distress or impairment. Criteria for diagnosing personality disorders are listed in the sixth chapter of the International Classification of Diseases (ICD) and in the American Psychiatric Association's Diagnostic and Statistical Manual of Mental Disorders (DSM).

There is no standard treatment for NPD. Its high comorbidity with other mental disorders influences treatment choice and outcomes. Psychotherapeutic treatments generally fall into two categories: psychoanalytic/psychodynamic and cognitive behavioral therapy, with growing support for integration of both in therapy. However, there is an almost complete lack of studies determining the effectiveness of treatments.