Citizenship plays a larger and more critical role in the life of children than it should. Children who lack citizenship are incredibly vulnerable to exploitation. In the migration context, a child’s citizenship can be largely determinative of where and with whom a child lives. Despite a modern children’s rights framework that recognizes the humanity and autonomy of children, citizenship and nationality still form an integral part of a child’s identity and play a critical role in a child’s development. It has a pervasive impact in securing other rights for children and can be a central factor in a child’s cultural and linguistic background, education, economic and environment exposures, and virtually all aspects of a child’s daily life. This chapter examines children’s right to citizenship and explores the ongoing crisis of statelessness that undermines these rights. It reviews the role that citizenship plays in both voluntary and forced migration of children, child-specific protections found in both universal and regional human rights frameworks, and the role of children’s citizenship in promoting family unity.