A narcissistic personality is characterized by a sense of entitlement, need for admiration, and pattern of self-centered behavior. While personality traits associated with narcissism are well known, the underlying neural correlates of this self-obsessed disposition are elusive. This chapter aims to provide an overview of the neuroscience behind narcissism by identifying the brain regions and networks that exhibit alterations when comparing individuals with grandiose or vulnerable narcissism to non-narcissistic study participants. Research concludes that frontal regions of the brain most likely underlie narcissistic tendencies, while frontostriatal connectivity, gray matter volume, and cortical thickness anatomically impact the development of narcissism. The connection between narcissism and other mental disorders is also explored, such as psychopathy, Cluster B personality disorders, and autism spectrum disorders (ASD). A limited number of studies suggests that future research is needed in order to confirm these relationships.