As teaching approaches have advanced, the role of technology and tools in learning has increased. Moreover, pupils’ Satisfaction with the implementation of these tools and technology should be considered too. To this end, the purpose of this inquiry was to examine the Iranian EFL learners’ Retention of Grammar knowledge and their Course Satisfaction based on Flipped classroom strategies. This quasi-experimental research had been carried out in the twelfth grade of Alvand private school in Tabriz city, East Azerbaijan, Iran. Forty high school learners were chosen as participants, and the homogeneity of the classes was checked through Oxford Quick Placement Test. Subsequently, participants were divided to groups in a random manner either the experimental group (n = 20) and the control group (n = 20). The pre-, post- and delayed post-tests of this research were from the Grammar in Use book, to check the initial knowledge, possible gained knowledge, and retention of acquired knowledge, as well as a questionnaire to investigate the level of their Satisfaction with their course. The independent-samples t-test revealed that the experimental group illustrated considerably higher proficiency than the control group in both post-test and ANCOVA scores. Moreover, the result of the questionnaire's descriptive statistics showed a high level of Satisfaction among learners. The study presents practical implications for teachers, researchers, and learners.
