Masculinity is a precarious social status, meaning it can be lost through social and gender transgressions (Bosson & Vandello, 2011). Men often act in stereotypically masculine ways to reassert their masculinity and restore their social status after it has been threatened. The current study also examines masculinity in a new way, as a collective gender identity (e.g., Tajfel, 1982). I hypothesized that threatened men and men who identify as more masculine will display masculinity through more polarized attitudes towards traditional and nontraditional groups of men and women, endorsing traditional gender stereotypes, and intensified ambivalently sexist attitudes. Two empirical studies tested these hypotheses. While the gender threat manipulation was unsuccessful, statistical analyses of results revealed relationships between masculine identification, ambivalent sexism, and gender stereotypes. Hostile sexism predicted negative attitudes towards nontraditional men and women, benevolent sexism predicted favorable attitudes toward men and women. Masculine identification predicted favorable attitudes towards masculine men and traditional women, and negative attitudes towards feminine men. Interestingly masculine identification did not predict unfavorable attitudes towards other nontraditional men. These results suggest masculinity is a collective identity, in which attitudes towards other men and women are influenced by in-group/out-group relations