Due to the current COVID-19 pandemic, all face-to-face instruction at higher education institutions (HEIs) worldwide has been suspended. Therefore, many institutions and universities relied on online learning to continue the instruction process. The perceptions of teachers and students who went through this experience can provide useful information regarding the success of the online instruction. Thus, the purpose of this study was to investigate the perceptions of teachers and students during the COVID-19 pandemic in Iran. Additionally, it aimed at exploring the main advantages and disadvantages of online instruction during this time. To this end, 250 English language teachers and students were selected from different English language institutes and universities in Iran. Drawing upon Khan et al.’s (2021) questionnaire and an open-ended question, this study showed that both teachers and students had positive perceptions towards online learning and teaching during COVID-19 lockdown despite the fact that some students had not the necessary facilities and infrastructure for online classes. Furthermore, this study showed that validity, reliability, construction, administration, and effectiveness of online assessment was a major concern for both teachers and students. Besides, both groups expressed the benefits of online instruction more than its drawbacks. The results of this study have implications for higher education teachers, and stakeholders to get a better understanding of the students’ and teachers’ perception toward online instruction
