This article identifies children’s rights as a neglected area in citizenship literature, both in socio-legal scholarship and in British nationality case law. It analyzes reasons for this neglect and posits that there exists a dichotomy in approaches to the wellbeing of children in the UK. The characterization of children’s interests and subsequent obligations owed by states to children are different in nationality law from other areas of law, notably, family law. Through our case study of the registration of children as British citizens, we argue that in the UK formal legal membership may appear achievable “in the books” but remains elusive in “law in action.” Children’s interests should be just as central to citizenship studies and nationality case law as to family law cases. A new approach to acquisition of British citizenship by children, with the best interests of the child as a critical evaluative principle at the heart of decision making, will usher in a new era. In the absence of such reconceptualization, children remain passive subjects of nationality law and their voices are unheard in processes of acquisition of citizenship.