The subject of this paper are the fundamental rights of migrant children in accordance with the European law. Due to their age, distance from home and country of origin, as well as separation from their parents or legal guardians (in case they are unaccompanied), migrant children are a particularly vulnerable group. For the biggest part, the rights of migrant children in Europe have been developed by the European Union and the Council of Europe. The most important documents that protect children’s rights are the Convention on the Rights of the Child at the international level, and in European law the European Convention on Human Rights, Charter of Fundamental Rights of the European Union and the European Social Charter. While dealing with unaccompanied children that are separated from their parents, all participants must respect one of the fundamental principles of children’s rights, which is the best interest of the child itself. All participants included in such a procedure, including police officers, are obliged to adhere to this principle during conducting certain actions towards unaccompanied children. Pursuant to the European Union law, the Charter of Fundamental Rights guarantees the right to asylum as a special type of legal protection to all people in the region of the European Union, including unaccompanied children, in addition to respecting the best interest of the child as well as other fundamental rights.