Abstract. The goal of the present investigation was to expand the literature on impulsivity and Cluster B personality disorders (PDs) by conceptualizing impulsivity in a multidimensional manner. Two separate undergraduate samples (n = 223; n = 204) completed measures of impulsivity and Cluster B dimensions. Impulsivity was indeed predictive of Cluster B dimensions and, importantly, each PD scale exhibited a unique impulsivity profile. Findings for borderline PD scores were highly consistent across samples and strongly and positively associated with urgency and lack of perseverance, as expected. Findings for the other PD dimensions also exhibited a fair amount of consistency. Implications of these findings for diagnostic classification and treatment are discussed.