Abstract This paper explores the hypothesis that contextual environments (media exposure and social exposure) and biospheric value orientation are important antecedents to the attitude-intention-behavior model ( Ajzen, 2001, 2002) in the context of environmental psychology. Data for this investigation were obtained from a random sample of 2106 (1073 males and 1025 females) high school students in Hong Kong. A path analysis demonstrates that adolescents’ social exposure and media exposure are associated with biospheric value orientation. The biosperhic value orientation is found to mediate between the contextual variables (media exposure and social exposure) and environmental attitude. This environmental attitude, in turn, mediates the relationship between this value orientation and behavioral intention to act environmentally. Results show that both adolescents’ behavioral intention and degree of social exposure are associated with their environmental behavior. Overall, this article provides empirical support for the proposed path model. The article concludes by presenting theoretical and practical implications for future research in environmental psychology.