The number of children on the move in Europe is without historical precedent. In theory, these children should enjoy protections as rich as anywhere in the world. In reality, European practices have been based on minimum standards of protection with a focus on specific (often procedural) rights. By examining how the Council of Europe and the European Union operate to protect human rights, this chapter explores how notions of the best interests of the child have been embedded in these two systems while attempting to control migration flows. It argues that both systems have considered the Convention on the Rights of the Child (CRC) and the CRC Committee as guidance for every context involving children, including for asylum and migration. Acknowledging the vulnerability of migrant children as a group with special needs, they stress the importance of integrating the best interests principle at legislative and administrative levels to pursue the ‘social development’ of children whatever their immigration status. As a result, while controversies persist, ‘Europe’ does provide a common protective foundation for migrant children. If it will grant a consistent approach on the rights of the child as an indivisible catalogue, it also offers a common potential for more sophisticated best interests-friendly solutions to prevail over the need to protect ‘national’ boundaries.