The prevailing justification for trademark law depends on economic arguments that cannot account for much of the law\u27s recent development, nor for mounting empirical evidence that consumer decisionmaking is inconsistent with assumptions of rational choice. But the only extant theoretical alternative to economic analysis is a Lockean natural rights theory that scholars have found even more unsatisfying. This Article proposes a third option. I analyze the law of trademarks and unfair competition as a system of moral obligations between producers and consumers. Drawing on the contractualist tradition in moral philosophy, I develop and apply a new theoretical framework to evaluate trademark doctrine. I argue that this contractualist theory...