Two experiments examined the variables characteristic of individuals who engage in responsible environmental behavior. In Exp 1, 142 Canadians (mean age 36 yrs) completed a phone survey which measured the relationship between environmental attitudes, perceived tactical efficacy of environmental activism, perceived threat, environmental knowledge, and recycling activism. No common set of factors was found to predict responsible environmental behavior. The lack of a common set of determinants was confirmed in Exp 2, which investigated factors distinguishing the composting vs noncomposting activity of 144 Ss (aged 31-50 yrs), and in Exp 3, which assessed predictors of 311 Ss' (mean age 45 yrs) energy efficiency investments. The implications for psychologists' roles in the development of environmental interventions are highlighted.