BACKGROUND: Little is known about the stress and burnout experienced by undergraduate and graduate nursing students during the COVID-19 pandemic. Academic burnout among nursing students can have an impact on students' learning ability, health, and wellbeing and on the quality of care and intention to leave the profession post-graduation. OBJECTIVES: Evaluate the predictors of nursing students' personal, academic, and collaboration-related burnout during the COVID-19 pandemic. DESIGN: Cross-sectional two-site study. SETTINGS: Icelandic universities offering nursing education. PARTICIPANTS: Graduate and undergraduate nursing students in Iceland (N = 1044) were asked to participate in the study, with a response rate of 32.7%. METHODS: An online survey was used to evaluate the students' stress and burnout in spring 2020. RESULTS: The main findings show that 51% of the variability in the students' personal burnout was explained by their perceived stress, mental health, and perceived support. Furthermore, the students' perceived stress, support, and educational levels predicted 42% of the variability in their academic burnout. Burnout related to collaborating with fellow-students was explained by the nursing students' physical health and by their educational level, explaining 6% of the variability in fellow-students burnout. CONCLUSION: University administrators might consider adding academic support facilities into their undergraduate nursing programs and teaching their students healthy coping skills.