Should girls and girl children fall into the same age category? Can the generic macro category of children, provided by international law starting with the Convention on the Rights of the Child, be considered adequate to satisfy the needs of social and legal protection of the different phases of development towards adulthood? These questions can raise serious sociological and juridical complications. As a result, without a clear definition in place, also the category of girl children risks being confused with the category of girls, and might not be noticed for its specific characteristics and needs. By using intersectional feminist theory, this analysis proposes a reflection on the necessity to adopt, both at a sociological and at a legal level, a more precise definition and conceptualisation of the terms girls and girl children.