Introduction: Mental health problem among university students during COVID-19 pandemic became one of the global main issues. There is limited study on mental health among university student during COVID-19 pandemic. Therefore, this study aimed to determine the associations between socio-demographic, body mass index, body image perception, physical activity and sleep quality with mental health among university students in Universiti Putra Malaysia. Methods: This is a cross-sectional study with a total sample of 130 students aged 18 to 25 years old which were recruited through a multistage sampling. An English online self-administered questionnaire was used to collect the data on socio-demographic characteristics, weight and height, body image perception (BSQ-8C), physical activity (GPAQ), sleep quality (PSQI), and mental health (DASS-21). Results: Majority of the respondents were female (76.2%), Malay (78.5%), in second year of study (28.5%), from low income family (59.2%) and stayed with parents during COVID-19 pandemic (57.7%). Results showed 44.6% of respondents had depressive symptoms, 56.9% had anxiety symptoms and 29.2% had stress symptoms with severity mild to extremely severe. Body mass index (r=0.205, p<0.005), body image perception (r=0.538, p<0.001), and sleep quality (r=0.460, p<0.001) were associated with depression subscale. Meanwhile, body image perception (r=0.449, p<0.001), and sleep quality (r=0.450, p<0.001) were correlated with anxiety subscale. Stress subscale was correlated with body image perception (r=0.473, p<0.001) and sleep quality (r=0.492, p<0.001). Conclusion: Affected students should be helped and referred to healthcare practitioner to ensure they able to overcome with these problems and remains healthy during this pandemic.