Alcohol consumption is a well-established risk factor for aggressive behavior. However, evidence suggests that alcohol's effect on aggression varies as a function of individual- and situational-based instigating and inhibiting factors. Endorsement of traditional masculine gender norms has been consistently identified as an instigating factor for alcohol-related aggression. Likewise, individuals who habitually engage in thought suppression (i.e., the attempt to inhibit the occurrence of unwanted thoughts) have been shown to be at increased risk for behavioral disinhibition and aggression. In the present study, we test the hypothesis that thought suppression mediates the association between masculine norms and alcohol-related aggression. Two hundred forty-five men with a history of recent heavy episodic alcohol use completed surveys assessing their endorsement of traditional masculine norms, use of thought suppression, and both trait and alcohol-related aggression. Results indicated that thought suppression fully mediated the association between the toughness masculine norm and alcohol-related aggression. In addition, thought suppression partially mediated the association between the toughness norm and trait aggression. Findings are discussed in terms of the potential utility of cognitive-emotion regulation and norm-based interventions for reducing alcohol-related aggression.