Using the International Criminal Tribunal for the Former Yugoslavia (ICTY) as a case study, this Article explores the merger of legal cultures at the ICTY. The ICTY was crafted in a high-stakes international environment and brings together lawyers and judges who have been trained and inculcated typically in a common law/adversarial system or a civil law/non-adversarial system. Lawyers and judges come to the ICTY not only with a distinct understanding of their roles within their home jurisdictions, but also with different skill sets. Merging the legal cultures has not always been smooth. By comparing how attorney-conduct norms are created in the United States—socialization, malpractice, market controls, regulatory processes, and procedural rules—with the practice at the ICTY, it becomes evident that the judges are the dominant source of norm creation in this international court. These norms are created, however, in an environment in which it appears that most of the substantive interaction between the judges, prosecutors, and defense counsel occurs in formal court settings. Future international courts would benefit from additional discussion among the judicial, prosecutorial, and defense functions as norms are created, including shared discussion about codes of conduct for judges, prosecutors, and defense counsel.