This focused ethnography considers children’s understandings and experiences of the body, and more specifically asks the question, ‘how do children come to know about the body?’. The study draws heavily upon the methodological ideas of the social studies of childhood, particularly the work of James (1993, 2013), to explore this question with nine and ten year old participants in two primary schools located in a northern English city. Findings highlight the complex interplay between structure and agency in understanding how children come to know about the body. Furthermore, children’s social and cultural locatedness, it is shown, shapes the ways in which they come to know about the body. Yet, the work of individual children in making sense of the body according to their particular experience is also highlighted. Indeed, it is through children’s experiential knowledge of the body that they come to challenge adult knowledge of, and control over, their bodies in school. Wider implications of the findings of this project include a more in-depth understanding of how children learn, which challenges the traditional notion that knowledge is passed down in a linear succession from adults to children. This, it is argued, has particular consequences in relation to understandings of children’s engagement with public health policy and formal learning about the body in school.