The present study aimed to investigate self-reported sleep quality and psychological well-being, specifically anxiety, depression and stress, in undergraduate students during home quarantine. A total of 7,364 students participated and completed the PSQI and DASS-21 scales. The results showed that higher-grade students were more likely to have mental health problems compared to their lower-grade students. Additionally, male students reported better sleep quality than females, and high-grade students reported more sleep problems than low-grade students. Significant correlations were observed between PSQI scores and stress, anxiety and depression scores (r=0.469, 0.458, 0.408, p<0.01). Specifically, the PSQI score explained 22.0%, 21.0% and 16.6% of the variance in stress, anxiety and depression scores respectively. In conclusion, gender and grade differences in sleep and mental health were evident, with female students reporting lower sleep quality than males, and high-grade students experiencing worse sleep quality and mental health than their low-grade students.