In response to evidence that one in five college women are sexually assaulted, institutions of higher education have started adopting affirmative consent policies. Affirmative consent must be voluntarily and explicitly communicated--verbally or nonverbally. A recently published article highlighted barriers to the success of affirmative consent initiatives at the intrapersonal level. To extend this discussion, we identified barriers at each level of the Social Ecological Model. In our commentary, we discuss social determinants that are particularly relevant for campus sexual assault. There are elements in young people's micro-, meso-, exo-, and macrosystems that hinder their adoption of affirmative consent practices. We focus on gender as an aspect of the macrosystem that is a formidable barrier to the success of affirmative consent initiatives, influencing each of the other levels. Finally, we discuss how sexuality education might begin to address the social determinants of sexual assault.