In this article, I discuss children's habitually underestimated agency capabilities in school life, including their potential as political subjects. Here, I present a description and analysis of an episode that took place in 2004, at a primary school located in a working class neighbourhood of Greater Buenos Aires, Argentina. On this occasion, a group of pupils, to shouts of “Justice!”, managed to get the headmistress of the primary school to dismiss a teacher who had mistreated them. This action altered the relative structure of authority in the life of the school and had an impact on basic assumptions regarding the seat of power and forms of justice. In my analysis of the episode, I relate this action to learning within scholastic and non-scholastic contexts, in which different experiences and interactions overlap with those of the social and cultural world of adults – in particular, with forms of social protest in the local community and neighbourhood, arising from the context of the 1990s. Although limited to this specific incident, interpretation of the occurrence permits me to bring into question concepts that ignore or underestimate children as cognizant and skilled in generating independent initiatives. I provide details of the circumstances under which the field work was carried out and during which this episode took place, making mention of the dialogical and performative character of the meetings with children within the framework of the ethnographic work. My argument is based on childhood anthropological works and on theoretical focuses regarding the contextual and interactive nature of learning.