Editors' Summary: In this Article, Prof. Ann Carlson argues that although appealing to environmental values as a means to instill behavioral change will, in most instances, work less well than reliance on other regulatory tools, voluntary behavioral change may nevertheless be necessary either to achieve marginal environmentally friendly behavior or because no good regulatory alternative exists. She therefore evaluates those circumstances in which there may be no alternative but to rely on voluntary behavioral change and suggests ways to increase such change. Professor Carlson finds that social norms may work well for convenient, one-shot behavior requiring no real sacrifice on the part of the individual. Conversely, a social norm is less likely to succeed in inducing behavior change if the requisite behavior is onerous or cumbersome, if the behavior requires sustained behavioral change, or if the individual gains something from engaging in the environmentally harmful behavior.