This study examined the hypothesis that self-monitoring moderates the relationship between Big Five personality traits and interpersonal performance. The findings from a sample of 102 employed Executive MBA students reveal that when self-monitoring was high the relationships between 3 of the Big Five personality traits (Extraversion, Emotional Stability, and Openness to Experience) and supervisory ratings of interpersonal performance were attenuated. These effects were replicated using peer ratings of interpersonal performance for Extraversion and Emotional Stability but not for Openness to Experience. Further, as expected, self-monitoring did not moderate the relationships between personality traits and supervisory or peer ratings of task performance. Implications for future research in the area of personality and other motivational theories are discussed.