Introduction: COVID-19 affects lifestyles, including those of undergraduate students who are one of the most vulnerable populations. This study aimed to describe changes in lifestyle-related behaviors and assess the correlation between the perceived risk of COVID-19, social support, perceived stress, and lifestyle changes among undergraduate students during the pandemic. Design and methods: A total of 547 students from 32 provinces in Indonesia completed online questionnaires comprising four measures: perceived risk of COVID-19, the Lifestyle-related Behavior Questionnaire, the Multidimensional Scale of Perceived Social Support, and the Pandemic-related Perceived Stress Scale. Results: Undergraduate students who lived with their families had healthier lifestyles than students who lived alone (p =0.007). Furthermore, The Pearson's correlation showed a significant correlation between lifestyle changes with perceived severity (r = 0.107; p < 0.05), social support (r= 0.237; p < 0.001 and pandemic-related stress (r= -0.304, p < 0.001). Higher perceived severity of COVID-19 and social support were associated with a healthier lifestyle, whereas increased stress correlated with a less healthy lifestyle. Conclusion: Psychological factors correlated with lifestyle changes of Indonesian undergraduate students during the pandemic. Therefore, psychological aspects should be more considered by relatives and institutions to ensure healthier lifestyles of students.