Every day, all around the world, millions of children are affected by immigration detention. Whether detained themselves or impacted by the detention of their parents or guardians, children are particularly vulnerable to abuse and neglect when subject to detention on the basis of their or their parents’ migration status. Regardless of the reasons for immigration detention, a number of studies have shown that detaining children has a profound and negative impact on child health and well-being. Migrant children deprived of liberty are exposed to increased risks of physical and sexual abuse, acts of violence, social discrimination and denial of access to education, health care, and family life. Even very limited periods of detention in so-called “child friendly” environments can have severe and lifelong impacts on child psychological and physical well-being and compromise their cognitive development. For these reasons, the immigration detention of children represents a serious threat to children, and a growing body of UN, regional, and domestic human rights experts have called upon States to “expeditiously and completely” end the practice. As a result, over the past five years the issue of child immigration detention has risen in importance on the global human rights agenda. United Nations, intergovernmental and civil society actors have undertaken significant research and reporting which finds that immigration detention is never in the best interests of a child, and have lobbied State policy makers to end the immigration detention of children as a matter of priority.