This Article generates a data set (twelve courts and thirty-two decisions) of foreign judicial citations to the landmark U.S. Supreme Court decision in Brown v. Board of Education. The purpose of this Article is to learn what happens when a case is deterritorialized and deconstituted in a different national scenario, and to conceptualize how courts around the world use foreign authority. My analysis reveals that few foreign courts used Brown in decisions involving education or race and ethnicity. Foreign courts used the case as a form of factual evidence, as a guide in understanding the proper role of a court with respect to decision making, and as a source of substantive law in discussions on equal protection. Although central to comparative law, the legal transplant metaphor does not adequately explain the transnational use of Brown. By incorporating sociological theories of diffusion and innovation, I attempt to reconcile some of the flaws of the transplant metaphor and argue that conceptualizing judiciaries’ use of foreign law as a cosmopolitan conversation is more appropriate. Cosmopolitan conversation has led to forms of legal learning and innovation when courts have cited, interpreted, and infused their own meaning into the Brown decision.