In early children education, play in the outdoor environment is considered important for all aspects of children's development. Three important elements in the curriculum process, identified from the early childhood literature, were selected for investigation in the thesis. These elements are the curriculum thinking and practices of teachers, the physical environments planned for children's play, and the children themselves. A series of studies was planned to examine the impact on the curriculum process of these elements separately, as well as their interrelationships. Firstly, a survey was conducted in 22 preschools to investigate provisions made by teachers for children outdoors. The results of this study confirmed the important role of the physical environment in the early childhood curriculum process, and highlighted some variations in preschool teachers' curriculum conceptions, and the diversity in their curriculum practices outdoors. Generally, teachers' provisions, and their expressed aims for children's experiences outdoors were not extensive. A more detailed study was then conducted in eight preschools. In the first part, teachers again were interviewed to explore, in greater depth, their conceptions of the outdoor curriculum. Results revealed that the variability in teachers' curriculum thinking evident from the first study reflected their personal understandings of developmental theory, their practical knowledge of children and teaching, and particular situational factors. Results also indicated the ways in which teachers' beliefs and theories about children's development and learning, and about the role of the adult in these processes, influenced the ways in which they plan the outdoor learning environment, and the expectations they have of children's, and teachers' behaviours in these settings. The second part of the investigation of the eight preschools examined the impact of teachers' curriculum approaches on children. It consisted of an observational study of the outdoor behaviour of 80 four year old children, with 10 children selected from each of the eight preschools. The results demonstrated that children experience considerable freedom in their outdoor play, and have relatively little contact with teachers. Outdoor settings support a diverse range of behaviours, although children's predominant activities were gross motor, pretend and manipulation. These activities occurred mainly in pairs and small groups, and involved similar high levels of parallel and cooperative play, as well as considerable verbal communication. Sandpits, open spaces, and fixed climbing structures were popular play locations, although children's preferences for these locations were related to the overall design of the playspace, as well as to individual child characteristics. Similarly, patterns of children's behaviour were related to specific features of the environment, as well as to children's gender. Together, the results of these studies demonstrated ways in which teachers, environments, and children, both separately and conjointly, influence the outdoor curriculum process. Results are discussed in terms of implications for the early childhood curriculum and for future research.