Objective: The purpose of the current study was to examine the bystander decision-making process as a mechanism by which men’s adherence to various dimensions of traditional masculinity is associated with their confidence to intervene in sexually aggressive events. Further, this study examined the stress men experience from their attempts to adhere to traditional male gender roles as a moderator of this mediational path. Method: Participants (n = 252) completed measures of traditional masculinity, decisional balance (i.e., weighing the pros and cons) for intervening, masculine gender roles stress, and bystander efficacy. Results: The belief that men must attain social status was associated with more confidence in men’s ability to intervene. This effect was mediated by greater perceived positive consequences for intervention among men high, but not low, in masculine gender role stress. The belief that men should be tough and aggressive was associated with greater perceived negative consequences for intervention and less confidence to intervene. The belief that men should not act in stereotypically feminine ways was directly associated with less confidence for intervention. Conclusions: Findings highlight the importance of examining masculinity from a multidimensional perspective to better understand how adherence to various norms differentially influences bystander behavior. These findings may help to inform bystander intervention programming. (PsycINFO Database Record (c) 2016 APA, all rights reserved)