Context: Promoting the quality of learning and teaching processes at the tertiary level, including distance education, has been considered as a strategic approach by policy makers in higher education, throughout the world. For this reason a reliable and comprehensive evaluation mechanism can play an important role in assessing the current situation and identifying the needs and problems from one hand and identifying the most important appraisal indicators on the other and. This study aimed at critically reviewing the literature and theoretical frameworks of previous relevant researches to highlight the most important components and indicators that must be applied in appraising distance education. Methods: As a qualitative study, a meta-synthesis approach was applied. Due to the importance of using the findings of previous studies as a foundation for extracting themost important appraisal indicators, 42 national and international research studies relevant to the evaluation of distance education were selected and analyzed, which were published in refereed journals during year 2006 to 2015. The eligibility criteria for selecting these studies were their relevance to any aspect of distance education. For this reason and in order to identify indicators, the content of these studies were analyzed based on the open coding method. Later on, all findings were categorized, outlined, and summarized according to the main components, which may form a comprehensive evaluation system for distance education at the higher education level. Results: The findings of this meta-synthesis showed that pedagogical knowledge, technology, learning organization, educator, learner, learning content, teaching models and strategies, time, place and space were the most important components of a comprehensive appraisal system that should be considered in evaluating distance education systems and its mechanisms and processes, continuously. Conclusions: The rise of distance education in Iran’s higher
