In this chapter, we review the developmental science of “Children and the Law” and our understanding of the diverse and broad array of cognitive, social, and emotional factors that developmental scientists have studied. To allow children to participate as fully as their abilities allow in legal decisions affecting their lives, it is important to understand their capabilities and strengths, as well as their cognitive and social limitations. We review the developmental science that provides an appropriate evidence base to thus improve decision‐making and outcomes for children and families within many aspects of the legal system. Since the previous edition was published in 2006, research has become increasingly “convincing” to nonpsychologists because basic laboratory research has been complemented by methods that have clear ecological validity, yielding findings that are better understood, accepted, and applied in legal contexts. This knowledge thus permits scholars to offer useful suggestions to practitioners and foster a more complete understanding of developmental processes. We first review the developmental trajectories in the principal domains of development known or likely to affect children in legal contexts—neurophysiological development, memory and suggestibility, cognitive development, language development, social and emotional development, and the development of social relationships with parents and peers. Secondly, we turn attention to the implications of normative developmental processes for children in a variety of legal contexts—investigative interviews with alleged victims, witnesses, and suspects, as well as for those children who are the focus of actions in family and dependency court. The chapter ends with an examination of the key questions to which researchers should turn their attention to further our understanding and practices concerning children and the law.