<p>The concept of sustainability in the United States (US) is deeply entrenched in sociopolitical identity discourse. It is critical that higher education institutions (HEIs) in the US identify barriers to sustainability behaviors in students of varying demographic social identities. This study explores whether students’ demographic social identities (i.e., political affiliation, childhood upbringing setting, and gender) could influence the relationship between their environmental identity and engagement in sustainability behaviors. Using secondary data from a sustainability survey at the University of Idaho (UI), a moderation analysis was conducted, using demographic social identities as moderators. The analysis revealed that environmental identity, gender, and political identities can directly predict students’ willingness to behave sustainably, but identity attached to childhood upbringing setting is not as strong a predictor. The analysis also revealed that demographic social identities do not significantly moderate the relationship between a student’s environmental identity and sustainability behaviors, demonstrating that environmental identity is an equally strong predictor of behavior across demographic groups. Overall, while demographic identities directly influence behavior, they do not influence the relationship between a student’s environmental identity and sustainability behaviors. The results of this study are valuable for HEIs operating in contexts where sustainability may be deemed polarizing or controversial.</p>