We conceptualized gender as a constellation of behaviors that a person both "has" and "does" to examine college students' endorsement of feminist and modern sexist attitudes. Men and women "have" internal, personal aspects of gender such as gender identification and stereotypically gendered traits, and they "do" their gender by engaging in stereotypically gendered activities and associating with peers. Men (n = 237) and women (n = 463) completed established self-report measures of gender identification, gender-typed personality traits, engagement in gender-typed activities, same-sex peer affiliation, feminism, and modern sexism. Structural equation modeling showed that correlates of feminist and modern sexist attitudes were different for men and women. For men, less endorsement of feminist attitudes was related to greater engagement in masculine activities, whereas engaging in feminine activities and endorsing feminine traits were related to more endorsement of feminist attitudes. Men who identified more with other men also reported attitudes that were less feminist and more modern sexist. For women, greater endorsement of masculine traits was associated with greater feminist attitudes, but engaging in masculine activities was related to less feminist attitudes. For women, none of the variables was related to sexist attitudes. Implications of these findings for understanding the development of feminist and sexist attitudes in U.S. college students are discussed.