Despite a heavy philosophical focus on issues pertaining to immigration, little discussion is taken up that examines the duties we owe to migrant children. This article works to bridge the gap between global justice literature and work on children’s autonomy and well-being. To capture what migrant children experience in the context of immigration and detention, the article examines the conditions on the island country of Nauru, where at least 222 migrant children experienced detention between the years of 2013 and 2019. Using this lived experience as an example, the article argues that we owe children specific positive duties, which are further supported by the Convention on the Rights of the Child. Throughout this article, the aim is to indicate how migrant children occupy a particularly vulnerable and nonautonomous status in the context of detention. Because of this, children are owed especially weighty positive duties that are not discussed in the current global justice literature.