This case study examines the development of self-regulation, socially, cognitively and emotionally, through the use of play in the curriculum in five preschool classrooms for children ages 2-5 years old at a university laboratory school. Five teachers were interviewed about their deliberate use of play to support the development of self-regulation in their students, and subsequently, each classroom was observed for a total of 2 hours over a period of 2 months. Data included interview transcripts, observational notes and photographs and videos of the classrooms and children's play. Findings showed that the teachers regarded play as central to their curriculum and to the development of self-regulation in their students. Observations demonstrate strong interaction between the curriculum, environment, routines and the development of self-regulation. Supporting the development of self-regulatory capacities is a social justice and equity issue most effectively addressed through the inclusion of play in the early childhood curriculum. (author abstract)