It is widely accepted that narcissists become aggressive when they experience ego-threat. However, there is surprisingly little empirical research on the relationship between narcissism and aggression. Equivocal findings suggest that aggression in narcissists either occurs only in response to provocation, or regardless of provocation. One-hundred and thirty-seven collegiate men completed the Narcissistic Personality Inventory followed by a sham aggression paradigm, which afforded them the opportunity shock, or refrain entirely from shocking an ostensible opponent confederate. Participants were identified as “unprovoked aggressors,” “retaliatory aggressors,” or “nonaggressors” contingent on when and if they chose to administer electrical shocks to the confederate. Results indicated that participants who were high on narcissistic traits were more likely to be unprovoked aggressors than their low narcissism counterparts. Results are discussed in relation to threatened egotism theory and call for more research on narcissism, aggression, and the moderating effect of provocation. Aggr. Behav. 36:414–422, 2010. © 2010 Wiley-Liss, Inc.