Three studies are reported which provide evidence for the validity of the Narcissistic Personality Inventory (NPI). Factor analysis of the NPI in Study 1 revealed four factors which were labelled: Exploitativeness/Entitlement, Leadership/Authority, Superiority/Arrogance, and Self-absorption/Self-admiration. In Study 2, scores on the NPI were correlated with basic dimensions of personality, and with relevant self-variables. Narcissism scores were positively related to dominance, exhibitionism, extraversion, self-esteem, and self-monitoring, among others; and negatively related to abasement, deference, and social anxiety, among others. Correlations between the NPI factors and personality variables are also examined. In Study 3, peer ratings of narcissism were obtained and it was found that these were strongly related to scores on the NPI. Taken together, the three studies provide considerable evidence for the construct validity of the NPI, and avenues for future research are suggested.