Children are participating in legal investigations and litigation more frequently than ever before. A better understanding of the development of children's conceptualization of the legal system is needed to understand fully the factors that affect children's behavior in the courtroom. Such information would be valuable to judges, jurors, attorneys, and policymakers who must assess children's competence to testify and credibility as witnesses. The information is critical to the efforts of parents, mental health professionals, and children's advocates who work to ensure that children are not revictimized, this time by the court system that is supposed to protect them. The first section of this article reviews existing literature on children's knowledge of social institutions, including the legal system. The second section describes a study, based in part on the findings of past studies, designed to compare the perceptions of different-aged children with varying amounts of experience in the legal system. Tables, footnotes, references