This article aims to explore legal consciousness and agency of unaccompanied migrant children in transit at the French-UK border. Based on long-term ethnographic fieldwork, this paper analyses how legal consciousness of migrant children is shaped by several and often intertwined factors, like police violence, harsh living conditions, and inadequate welfare protection. It highlights that children’s (non-)use of the law should not be seen as proof of a lack of agency, but rather as the result of a specific set of biographical experiences and contextual factors, such as their interactions with administrations and institutions in Europe, the influence of migrant adult peers and their own migration projects. The contribution shows that the combination of these elements deeply impacts legal consciousness of unaccompanied minors, influencing their (non-)use of legal tools.