This chapter explores the theoretical and legal foundations of child-friendly justice as an emerging trend in global legal and judicial reform. Drawing on insights from human rights law, the sociology of law, and developmental psychology, it argues that child-friendly justice represents a shift away from traditional juvenile justice models toward frameworks that prioritize children’s rights and meaningful participation. The discussion identifies five key principles that underpin this approach: the best interests of the child, the right to be heard, non-discrimination, humane and accessible justice, and procedures that reflect the child’s age and development. These principles form the normative core of a child-sensitive legal system.