This paper explores the relationship between identity registration and the regulation of child labor in colonial Tanganyika. The lack of identity registration in colonial Africa rendered childhood a malleable concept that could be variously manipulated. In Tanganyika, children were employed in both industrial and agricultural settings, working for both kin and non-kin, including in large colonial concerns. The lack of age data precluded regulation of labor and sparked debate about how to identify a child. Different actors defined “childhood” to suit their own ends, leading to both the exploitation and the empowerment of the Tanganyikan child. The discussion is situated against wider consideration of the role of civil registration in enabling child protection.