Despite being significantly correlated, there is evidence to suggest that the scales measuring Agreeableness from the Big Five Inventory (BFI) and the Revised NEO Personality Inventory (NEO PI-R) do not capture identical constructs. More specifically, NEO PI-R Agreeableness contains content related to "honesty and humility" that is not contained by the BFI. In a sample of undergraduates (N = 290), the authors compared the correlations between these two measures of Agreeableness with traits from the HEXACO-PI-R as well as measures of narcissism, narcissistic personality disorder, and psychopathy. As expected, the two scores were significantly correlated but NEO PI-R Agreeableness manifested stronger correlations with the domains/facets of Honesty-Humility, narcissism/NPD, and aspects of psychopathy; these differences appear to be due primarily to the inclusion of the NEO PI-R facets of Straightforwardness and Modesty. These differences have important implications for the assessment and conceptualization of personality and personality disorder. (Contains 1 table.)