In this paper I critically examine the nature and function of developmental discourses in school physical education. Current legitimations for the inclusion of physical education as a subject in the school curriculum tend to centre around its instrumental value in contributing to physical, social, emotional and psychological dimensions of children's development. Underpinning such claims are common sense and professional understandings about the "nature" of children and a legacy of ideas about how children "develop." Recent work by critical psychologists and some poststructuralist writers has critiqued the notions of child development informing physical education policy and professional activities. Drawing on insights from poststructuralist theory, I will consider both the challenges and implications a critique of "developmentalism" presents for physical educators in schools.