Objective: This study aimed to draw a general picture of the impact of the coronavirus dis ease 2019 (COVID-19) pandemic on the life of higher-education students in İstanbul, withspecific emphasis on the relationship between students’ social support systems, health risk behaviors, and mental/academic well-being. Methods: A total of 2583 higher-education students from different fields of study par ticipated in an online survey gathering information from several domains, including avail able social networks, support-seeking attitudes, substance use patterns, physical activitylevels, academic stress, academic satisfaction, and psychological well-being during thepandemic. Results: Our findings pointed to major changes in students’ life circumstances and dailyroutines during COVID-19, including a significant decrease in contact with friends, over all substance use, and physical activity as well as high levels of depression, academicstress, and academic dissatisfaction. Depressive symptoms were significantly predictedby the loneliness score (OR=2.08, 95% CI=1.88-2.29), female gender (OR=1.65, 95%CI=1.21-2.24), frequency of binge drinking (OR=1.4, 95% CI=1.06-1.86), and level of aca demic stress (OR=1.15, 95% CI=1.1-1.19), whereas the number of people to easily bor row money from was found to be a protective factor against depression (OR=0.95, 95%CI=0.92-0.99). Conclusion: Our results highlight the need for higher-education institutions to take theappropriate social and mental health interventions, tailored to fit the specific require ments of the COVID-19-related measures.