This study examines the extent to which implicit measures of aggressiveness predict actual aggressive behavior in response to provocation. Participants (n = 77) completed implicit measures of aggressiveness, were or were not exposed to insult from an experimenter, evaluated the performance of the experimenter (i.e., opportunity for aggressive behavior), and completed explicit measures of aggressiveness. Results showed that the implicit measure of aggressiveness significantly predicted aggressive behavior in response to provocation, whereas it was not predictive when there was no provocation. The discussion deals with the validity of implicit measures as predictors of aggressive behavior and their moderators.