There are important gaps in our knowledge about children who migrate. Even in societies which employ technologically sophisticated systems for monitoring and measuring migration, data on child migrants are incomplete and focused on specific groups of vulnerable children and young people. The lack of data and research on processes underpinning child migration and on the experiences of children who migrate are rooted in hegemonic Westernised assumptions about, and constructions of, childhood, family migration, and migration in general. Migrant children are represented as passive, needy and different; their accounts of themselves and their lives are silenced through adultist discourses about migration decision-making and experiences. The papers in this special edition of JEMS challenge these constructions of migrant children by focusing on the children's experiences in a multiplicity of migratory contexts. Presented first at the international conference 'Children and Migration: Identities, Mobilities, Belonging' organised by the Marie Curie Migrant Children Project at University College Cork, Ireland, in April 2008, the papers showcase emerging research which challenges the adult-centric nature of migration research and policy.