This introductory article sets out the main challenges that the study of children poses for the understanding of transnational migration. Children are not simply a neglected empirical group, whose perspectives are rarely considered; children can also provide researchers with important insights concerning the nature of transnationalism if the phenomenon is considered through their eyes. Research on transnational children brings to the fore issues concerning familial practices and discourses, the importance of the life-course and of generation, and the role of feelings in creating and changing transnational relationships and imaginaries. Focusing on children and children's places raises important questions concerning the relationship between the life-course and the global political economy. Finally, researching with children raises particular methodological challenges and approaches.