Studying the way that decisions are made and plans are drawn for the academic calendar could lead to the recognition of probable problems and the necessary improvements. This in this paper, the extent of the instructional time in Iran is compared to that of some other countries and the difficulties of the currents academic calendar are examined. The method used is descriptive/ analytical and the statistical population was consisted of three groups of high school teachers, principals, and teaching experts in Esfahan and Yazd from which 180 teachers and 35 principals were selected randomly. The selection of 16 experts was not random? A questionnaire was used to collect data from the first two groups. The experts were interviewed.The results indicate that the real time spent on learning/ teaching in Iran is lower than that in the developed countries. Furthermore, the academic calendar seems to have prepared the grounds for some difficulties such as learners' anxiety, teachers fatigue, discouragement, early burnout, and reduced efficiency.