We addressed whether narcissism and self-esteem synergize to enhance assertive responses and deter aggressive responses to ego-threatening provocation. Participants (N = 448) completed measures of narcissism and self-esteem, imagined ego-threatening provocation, and indicated their aggressive and assertive responses. Participants also completed individual difference measures of agreeableness, openness, status/dominance motivation, and endorsement of the notion that aggression begets power. Narcissism and self-esteem interacted to reduce aggressive responses but enhance assertive responses to ego-threat; moreover, this interaction related to enhanced agreeableness, openness, status/dominance motivation, and reduced endorsement of the belief that aggression begets power, and these relations accounted, in part, for relations between the interaction and aggressive and assertive responses. Broadly, the findings contribute to the contentious issue of how self-evaluation influences responses to ego-threat; specifically, we would suggest that this issue be conceptualized in terms of synergistic effects of narcissism and self-esteem and distinguish between assertive versus aggressive responding.