ObjectivesThe overall objective of this article is to contribute to the identification of underlying factors causing individuals’ pro-environmental behavior (PEB).MethodsThis is done by the amalgamation of an empirically-derived theory originating in the behavioral science research—the value-belief-norm (VBN) theory (e.g., Stern et al., 1999)—and a rather recently developed theory in political science—the ecological citizenship (EC) model (e.g., Dobson, 2003). Using survey data, this article empirically tests the explanatory power of these two theories, both separately and as a joint model.