One of the life areas under the impact of the COVID-19 pandemic is university education. As it becomes more prevalent with its various versions, it shapes undergraduates' psychological well-being profoundly. It is necessary to understand how COVID19-related stress impacts their mental life. The purpose of the study was to examine whether COVID-19 burnout and cognitive emotion regulation had mediating roles in the relationship between COVID-19-related stress and life satisfaction. Three hundred sixty-four Turkish undergraduates participated in the study. Mediational analyses showed that both adaptive and maladaptive cognitive emotion regulation had interplaying roles in the link between COVID-19-related stress and life satisfaction, unlike COVID19 burnout. Yet, COVID-19-related stress indirectly affected life satisfaction since COVID-19 burnout increased maladaptive cognitive emotion regulation strategies while decreasing adaptive ones concurrently. The findings are crucial for mental health professionals whose aim is to develop necessary psychological interventions for undergraduates to increase their life satisfaction levels during the COVID-19 pandemic.