A stressful condition such as the emergence of the coronavirus and its related lockdown measures might trigger alterations in college students' behaviors. This cross-sectional study aimed to identify the changes in college students' dietary and lifestyle behaviors during the lockdown and the effect of lockdown-related stressors on health-risk behaviors. A web-based survey was conducted among undergraduate college students in Jordan. Weight and height were reported by the students. The students' dietary and lifestyle behaviors and their changes during 1 month of the countrywide lockdown were assessed. The Perceived Stress Scale-4 was utilized to assess stress levels. Results indicated that 77.2% of the students reported weight changes. Notably, 45.9% increased their intake of unhealthy food, while and 38% opted for healthier food choices. Most students experienced alterations in physical activity (80.0%), screen time (86.2%), smoking, and sleep patterns (85.4%), with a higher tendency toward adopting health-risk behaviors. Perceptions of curfew-related stress were associated with distance learning-related stress (OR = 2.73, CI: 1.08-6.90, P = .034), and a greater change in physical activity (OR = 3.59, CI: 1.36-9.48, P = .010). Additionally, weight changes were associated with perception of other types of stressors (OR = 3.39, CI: 1.39-8.28, P = .007). Overall, there was a considerable increase in malnutrition and health-risk behaviors among students during the lockdown. Understanding students' responses to these stressful conditions and the role of stress in driving behavioral changes are crucial for developing interventions that enhance college students' adaptation to such changes and maintaining healthy dietary and lifestyle behaviors in the future.