Abstract: Title VII provides symmetrical protection against discrimination in that both blacks and whites, and men and women may avail themselves of the law’s protections. In contrast, the Age Discrimination in Employment Act operates asymmetrically, shielding workers over the age of forty from discrimination yet offering no reciprocal protection for younger workers. Why do some antidiscrimination laws protect symmetrically while others do not? More importantly, why does this design choice matter? These are questions that scholars, courts, and legislators have generally ignored. This Article proceeds in two parts. First, it identifies symmetry as an important, yet frequently overlooked, way in which American antidiscrimination laws differ. Second, it proposes the “symmetry principle” as a major normative theory for analyzing and evaluating the design of antidiscrimination laws. Symmetrical laws have unique expressive, tactical, and substantive strengths. For example, symmetrical laws promote solidarity, are more politically palatable, can more effectively challenge stereotypes, and are capacious enough to respond to unanticipated forms of bias. This Article defends symmetry as a default rule to be applied when addressing traits such as sex, age, and genetic information. To comprehensively combat discrimination, however, the law cannot rely exclusively on symmetry; rather, asymmetrical laws can under certain circumstances be uniquely beneficial. Sometimes a trait is not universally held and is most intelligible as an asymmetric measure, such as in the case of disability. At other times, protecting symmetrically would mean giving advantaged groups a “reverse” cause of action that might further subordinate an already disadvantaged group, such as in the case of disability. Accordingly, this Article defends asymmetrical approaches to disability as well as several race-based policies and doctrines. Taken together, the symmetry principle is capable of imposing some degree of order on the wide-ranging policies and practices in antidiscrimination doctrine. In addition to addressing this previously neglected design choice, and considering how current laws might be modified to better prevent and rectify subordination, the symmetry principle and its analytical framework may also assist future legislative bodies in crafting new antidiscrimination measures that are directed toward formerly unprotected groups.