Indices were developed to assess discomfort with specific behavioral violations of gender heteronormative gender roles, gender identity, and sexual orientation. A three-component model that proposes specific threats to social status as mechanisms of gender-based prejudice was then used to assess whether homophobia and transphobia were triggered by the non-gender heteronormative social identity status of the outgroup member or by perceived violations of specific gender heteronormative behaviors. For a sample of 145 female and 194 male gender heteronormative U.S. college undergraduates, path analyses showed that homophobia was particularly associated with discomfort with violations of sexual orientation norms while transphobia was particularly associated with discomfort with violations of gender identity norms. For men and women, discomfort with sexual orientation norms significantly mediated the relationships linking right-wing authoritarianism and benevolent sexism to homophobia while discomfort with violations of gender identity norms significantly mediated the relationships linking right-wing authoritarianism and benevolent sexism to transphobia. Discomfort with sexual orientation norms significantly mediated the relationships between religious fundamentalism and homophobia for men only, while this same discomfort mediated the relationship between benevolent sexism and homophobia for women only. A significant direct path from physical aggression proneness to homophobia was found for men only.