In 1947, Naif al Zir’ini submitted a petition to the High Commissioner of Palestine on behalf of his son, Ahmad, who had been convicted of rape and sentenced to a term of hard labor. Al Zir’ini claimed that, under the government’s own laws, his son should have been sentenced to serve his time in a reformatory school as he was under the age of sixteen. Furthermore, the father wrote, he had given his son’s birth certificate to the police, but the police had neglected to turn it over to the court. “Your Excellency,” the petition concluded, “the imprisonment of a child is neither in accordance with the law nor with conscience.” The colonial socio-legal structure that Naif al Zir’ini confronted in the waning days of Mandate Palestine claimed the power to make and unmake childhood. The questions at the heart of his son’s case were: what did childhood mean in the context of the criminal law, did Ahmad “count” as a child, and who held the power to decide? Like other institutions of child welfare in Palestine during this period, the Mandate’s juvenile delinquency regime both constituted the child as a new subject of governance and rendered that subjecthood precarious, able to be taken away through the deployment of legal, medical, or sociological expertise. Using Nadera Shalhoub-Kevorkian’s concept of “unchilding,” this paper examines how childhood was in turns bestowed and denied to the young people who passed through the Mandate’s criminal justice system. Employing the governmental records of young offender cases, it argues that the same institutions and instruments that constructed children as a new category of governable subject – the scientific disciplines of sociology and psychology, forensic medicine, and theories of child development – were also the mechanisms through which childhood was dismantled and revoked. Furthermore, this paper shows that the process of childing and unchilding Palestinian youth in the Mandate period was realized within the interactions between the legal structures of the government and the socio-political specificities of local communities. Who got to be a child and how childhood was granted was an arena of contestation between the rhetorical and physical power of colonial law and the actions and advocacy of parents, families, and the young offenders themselves.