This thesis addresses the need to clarify the meaning of the open learning concept. It does so from a curriculum perspective and with a particular focus on curriculum control. The reason for this is that open learning is said to involve control of curriculum by learners. The study draws on curriculum theory to identify three alternative conceptions of curriculum which are used as alternative ways of considering open learning. Thus, open learning is examined as an element of social theory, as an intended curriculum and as a perceived student learning experience. The analysis is facilitated by the development of a suite of analytical tools, comprising curriculum code theory and the concepts of frame and decision-making space. Students are considered as curriculum decision-makers in order to investigate their latitude for curriculum control from their own perspective. By comparing the three conceptions of open learning listed above as they apply to a particular case of open learning provision, by analysing that case in terms of the suite of analytical tools and by considering the relevant historical and socio-cultural context, a new theory of open learning is generated. The new theory implies that a systems wide, rather than a piecemeal, approach to the development of national systems of open learning is needed. In Australia, this means fully integrating the Initiative within the Unified National System of Higher Education and making its funding base and systems of student support more equitable with conventional provision. The study identifies the learners' context as a significant but previously unacknowledged constraint on students' decision-making and learner control of curriculum. It notes that transfer of control over entering a program of study is not automatically conferred by an open admissions policy but is, instead, dependent on providers meeting the information needs of students.