The growing interest in the study of narcissism has resulted in the development of a number of assessment instruments that manifest only modest to moderate convergence. The present studies adjudicate among these measures with regard to criterion validity. In the 1st study, we compared multiple narcissism measures to expert consensus ratings of the personality traits associated with narcissistic personality disorder (NPD; Study 1; N = 98 community participants receiving psychological/psychiatric treatment) according to the Diagnostic and Statistical Manual of Mental Disorders (4th ed., text rev.; DSM-IV-TR; American Psychiatric Association, 2000) using 5-factor model traits as well as the traits associated with the pathological trait model according to the Diagnostic and Statistical Manual of Mental Disorders (5th ed.; American Psychiatric Association, 2013). In Study 2 (N = 274 undergraduates), we tested the criterion validity of an even larger set of narcissism instruments by examining their relations with measures of general and pathological personality, as well as psychopathology, and compared the resultant correlations to the correlations expected by experts for measures of grandiose and vulnerable narcissism. Across studies, the grandiose dimensions from the Five-Factor Narcissism Inventory (FFNI; Glover, Miller, Lynam, Crego, & Widiger, 2012) and the Narcissistic Personality Inventory (Raskin & Terry, 1988) provided the strongest match to expert ratings of DSM-IV-TR NPD and grandiose narcissism, whereas the vulnerable dimensions of the FFNI and the Pathological Narcissism Inventory (Pincus et al., 2009), as well as the Hypersensitive Narcissism Scale (Hendin & Cheek, 1997), provided the best match to expert ratings of vulnerable narcissism. These results should help guide researchers toward the selection of narcissism instruments that are most well suited to capturing different aspects of narcissism.