As a result of the advent of the COVID-19 outbreak, online assessments are being implemented in universities and schools worldwide. Nevertheless, regardless of the extensive use of online assessments, many researchers have proposed several barriers to the effective application of this form of examination in different language learning contexts. A combined qualitative and quantitative methodological approach was used to investigate 154 Iranian English language learners' opinions of the relative benefits of online examinations in terms of pedagogy, validity, reliability, affective factors, practicality, and security during the COVID-19 pandemic. To this end, an electronic questionnaire and semi-structured interviews were employed. This study identified online assessment as having significant benefits over traditional, paper-based examinations, comprising accessibility, using cutting-edge technology, providing immediate feedback, automated grading, creating a question bank, and long-term efficiency in terms of time, effort, and costs. Nevertheless, many challenges have been identified by students while successfully implementing online exams regarding validity and reliability, emotional and security issues.