A variety of social factors are expected to contribute to health behaviors among college students. The goal of this paper is to describe the relationships of two different aspects of the campus social environment, namely the campus resources for gay, lesbian, and bisexual (GLB) students and the campus-wide behavioral norms of substance use, to the individual substance-use behaviors of college students with same-sex experiences. Individual-level data come from 630 college students reporting same-sex experience, who were part of a national random sample returning questionnaires. Current cigarette smoking and binge drinking were examined. College-level data regarding the campus resources designed for GLB students were collected and used with campus-wide substance-use norms to predict individual substance use in logistic regression analyses. One-third to one-half of students reported current smoking and binge drinking, by sex and sex-partner category. The presence of GLB resources was inversely associated with women's smoking and directly associated with men's binge drinking behaviors. The proportion of students reporting same-sex behavior on campus was directly associated with these same outcomes, and behavioral norms were not associated with either outcome. Findings provide a glimpse into the influence of the social environment on the use of two of the most widely used substances at American colleges, and suggest that contextual approaches to explaining and controlling substance use may be important.