Introduction: This study aims to examine the determinants of academic performance among students in Faculty of Medicine and Health Sciences (FMHS) in Universiti Putra Malaysia (UPM) during COVID 19 pandemic. Method: A cross sectional study was conducted between 1st March 2021 until 15th March 2021 to determine the factors associated with academic performance during COVID 19 pandemic among medical students in a public university. The questionnaires of COVID-19 Fear Scale, Student Stress Inventory-Academic Subscale, and self-reported academic performances were used. Results: The study revealed that lower stress level (OR 0.938, 95% CI 0.893-0.984), being non-medical students (OR 3.210, 95% CI 1.844, 5.587) compared with medical students, Chinese ethnicity (OR 2.932, 95% CI 1.635, 5.258) compared with non-Chinese ethnicity and a conducive study environment (OR 1.954, 95% CI 1.168, 3.268) compared with non-conducive study environment were the determinants of good academic performance among undergraduates in a public university during COVID 19 pandemic. Conclusion: These findings indicate that low stress level, non-medical course, Chinese ethnicity, and good study environment are significant factors associated with good academic performance during COVID-19 pandemic among undergraduate students in a public university. Therefore, institutions may benefit from taking these factors into account when developing interventions to enhance students’ academic outcomes.