This study aims to understand the relationship between masculinity and the endorsement of attitudes towards guns and violence and aggressive fantasies. I examine threatened masculinity and masculine gender role stress in addition to a newly developed measure, which assesses traits associated with incels, who believe that social liberalism, feminism, and more sexually active men (“Chads”) are to blame for their lack of sex with women. Incels are largely a disorganized group of men interacting online, but a few self-identifying members have been associated with a number of mass violence events in recent years. The data were constructed from an original self-report survey distributed to men aged 18 to 30 years old, the group most responsible for violence against women and mass violence. I hypothesize that men who perceive that men are losing status as a group (status threat) (1), who feel less acceptance as members of that category (acceptance threat) (2), or who exhibit incel traits (3) are more likely to (a) approve of guns, violence, and aggression, and (b) exhibit aggressive fantasies. This study’s findings support three hypotheses: status threat is positively associated with an approval of guns and violence; acceptance threat is positively associated with approval of guns, violence, and aggressive fantasies; and incel traits are positively associated with aggressive fantasies. Men who experience status or acceptance threat or share incel traits exemplify issues of toxicity present in masculinity today. Their support for gun use, violence and aggressive fantasies further show the connection between male insecurity, aggressive attitudes, and fantasizing about violence. / M.S. / This study aims to understand the relationship between masculinity and the endorsement of attitudes towards guns and violence and aggressive fantasies. I examine masculinity and feelings of threat in addition to a newly developed measure, which assesses traits associated with incels (“involuntary celibates”), who believe that social liberalism, feminism, and more sexually active men are to blame for their lack of sex with women. Incels are largely a disorganized group of men interacting online, but a few self-identifying members have been associated with a number of mass violence events in recent years. The data were constructed from a survey distributed to men aged 18 to 30 years old, the group most responsible for violence against women and mass violence. I hypothesize that men who perceive that men are losing status as a group (1), who feel less acceptance as members of that category (2), or who exhibit incel traits (3) are more likely to (a) approve of guns, violence, and aggression, and (b) exhibit aggressive fantasies. This study’s findings support three hypotheses: feelings of group status loss are positively associated with an approval of guns and violence; stress in one’s masculine gender role is positively associated with approval of guns, violence, and aggressive fantasies; and incel traits are positively associated with aggressive fantasies. Their support for gun use, violence and aggressive fantasies further show the connection between male insecurity, aggressive attitudes, and fantasizing about violence.