The situation of the coronavirus (COVID-19) pandemic is full of unpredictability, uncertainty about the severity of the disease, and incorrect information. Therefore, health literacy preparation is the key to preventing COVID-19 and having the correct health behaviors. The objectives of this study were 1) to study health literacy on COVID-19 and prevention behaviors of COVID-19 among undergraduate students at Mahasarakham University, and 2) to compare health literacy on COVID-19 and prevention behaviors of COVID-19 among undergraduate students at Mahasarakham University, classified by genders, academic years, grade point averages (GPAs), and faculty groups. The participants were 417 undergraduate students at Mahasarakham University chosen by stratified random sampling and simple random sampling. The research instruments were as follows: the questionnaire on health literacy on COVID-19 and the questionnaire on COVID-19 prevention's behavior. The data were analyzed using percentage (%), mean (M), standard deviation (S.D.), independent sample t-test, one-way ANOVA. The findings revealed that 1) undergraduate students were well versed in health literacy for the COVID-19 infection and their prevention behaviors of COVID-19 infection were at a good level (M = 90.06, S.D. = 9.54; M = 86.87, S.D. = 11.50) and 2) female undergraduate students had statistically higher mean scores on COVID-19 health literacy scores and COVID-19 prevention's behaviors than males. Students from the health sciences faculty group had statistically significantly higher average health literacy scores on COVID-19 infection than those from the technology sciences faculty group.