College students have poorer mental health than their peers. Their poorer health conditions seem to be caused by the greater number of stressors to which they are exposed, which can increase the risk of the onset of mental disorders. The pandemic has been an additional stressor that may have further compromised the mental health of college students and changed their lifestyles with important consequences for their well-being. Although research has recognized the impact of COVID-19 on college students, only longitudinal studies can improve knowledge on this topic. This review summarizes the data from 17 longitudinal studies examining changes in mental health and lifestyle among college students during the COVID-19 pandemic, in order to improve understanding of the effects of the outbreak on this population. Following PRISMA statements, the following databases were searched PubMed, EBSCO, SCOPUS and Web of Science. The overall sample included 20,108 students. The results show an increase in anxiety, mood disorders, alcohol use, sedentary behavior, and Internet use and a decrease in physical activity. Female students and sexual and gender minority youth reported poorer mental health conditions. Further research is needed to clarify the impact of the COVID-19 pandemic on vulnerable subgroups of college students.