Online health information-seeking behaviour has increased since the World Health Organization declared COVID-19 a global pandemic in March 2020. This study examined whether health-related information on COVID-19 searched on the internet was associated with mental well-being among higher education students. A cross-sectional internet survey was conducted among 18- to 34-year-old students in Finland (N = 2976; mean age 24.61 years and median 24) in the spring of 2020. The data were analysed using descriptive statistics, Pearson’s chi-square tests, Kruskal–Wallis nonparametric H tests, and a two-way ANOVA. The results indicated that most students (86% of females, 82% of males) used the internet to search for information on COVID-19. Students’ self-perceived abilities to determine the relevance of online information on COVID-19 were associated with mental well-being.