Although there is now a considerable literature on how law and legal principles serve as institutionalized models for organizations, there has been far less attention to how organizational practices may serve as institutionalized models for courts. This article offers a theoretical and empirical analysis of legal endogeneity -a subtle yet powerful process through which institutionalized organizational structures and practices influence judicial conceptions of legality and compliance with antidiscrimination law. We argue that, irrespective of their effectiveness, organizational structures, such as grievance procedures, anti-harassment policies, evaluation procedures, and formal hiring procedures, become symbolic indicators of compliance with anti-discrimination laws, first within organizations, but eventually in the judicial realm as well. As organizational structures become increasingly institutionalized, lawyers and judges become more likely to associate them with rationality and fairness and to infer nondiscrimination from the mere presence of those structures. Legal endogeneity has observable manifestations: judges increasingly refer to organizational structures in their opinions, find them relevant to determinations of legal liability, and ultimately defer to those structures by inferring nondiscrimination from their presence. We test legal endogeneity theory by analyzing a random sample of 1024 federal employment discrimination decisions from 1965-1999. We find that legal endogeneity has increased over time; that judicial deference is most likely when plaintiffs lack social and economic clout; and that judicial deference is most likely when the legal theories require judges to rule on organizational attributes that are not directly observable. We suggest that legal endogeneity weakens the impact of law as judges come to view organizational structures as indicators of legal compliance even when those structures are ineffective in combating discrimination.2