Learning transfer and prosocial behavior (PSB) are critical components of many outdoor education programs for adolescents. This study examined the effects of a theoretically grounded treatment curriculum designed to foster the transfer of learning of general and contextual PSB (also called expedition behavior) among adolescents enrolled on 14-day backpacking courses with the National Outdoor Leadership School. Results suggest that the treatment curriculum increased proximal learning of PSB more than courses that featured the traditional curriculum. Qualitative results suggested that students learned PSB primarily as a result of its relevance to the expedition environment, that it is most useful when working with or understanding others, and that it can be applied to multiple contexts post-course, including with family, at school, and with sport teams. Implications for designing a curriculum that fosters transfer and for developing PSB in participants are considered.