Much research has examined individuals' values and beliefs as antecedents or correlates of pro-environmental behaviors (PEB). We approach this question from the novel perspective of individuals' cosmopolitan orientation (CO). We define CO as made up of three essential qualities. First, cultural openness captures individuals' receptiveness to immerse in and learn from other cultures. Second, global prosociality denotes a sense of collective moral obligation to universally respect and promote basic human rights. Third, respect for cultural diversity concerns high tolerance of and appreciation for cultural differences. Across two studies, we validated the Cosmopolitan Orientation Scale (COS) with theoretically related criterion measures across Singaporean, Australian, and American samples. Analyses showed good fit with a three-factor model. Next, we demonstrated the theoretical utility of CO, in particular the global prosociality subscale, in predicting PEB above and beyond pro-environmental worldview, motivation, and belief.