Distance Education (DE) theorists have argued about the requirement for a theory to be comprehensive in a way that can explicate many of the activities associated with DE. Currently, Transactional Distance Theory (TDT) (Moore, 1993) and the Theory of Instructional Dialogue (IDT) (Caspi & Gorsky, 2006) are the most prominent theories, yet they still do not represent a unified and comprehensive theory for DE. This paper provides a review of the existing literature on DE theories and identifies potential gaps in theorising distance education. Building on Giddens' (1984) work, an innovative approach to theorising DE is proposed through the conceptualisation of the "Adapting Structuration Theory In Distance Education" (ASTIDE) model as a means to explicate DE operations and practices at the institutional and national/international level. It also presents evidence, from a larger study, of the necessity of a comprehensive model such as the ASTIDE constructed through an investigation into the DE systems of developing and developed countries.