The coronavirus disease 2019 (COVID-19) has left tertiary students feeling anxious, stressed, and depressed. As a result, online counseling is a new option for students seeking counseling to alleviate stress and anxiety. The aims of this study were to 1) investigate undergraduate students' attitudes towards online counseling since the COVID-19 pandemic, and 2) compare the attitudes of undergraduate students at Mahasarakham University towards online counseling since the COVID-19 pandemic, classified by gender, academic year, grade point average (GPA), faculty, experience in face-to-face counseling, and experience in online counseling. The participants were 417 undergraduate students from Mahasarakham University who were selected by using a convenient sampling method. The research instrument was the questionnaire on undergraduate students' attitudes towards online counseling. The researcher used percentage, mean, standard deviation, independent sample t-test, and one-way ANOVA to analyze the data. The findings indicated that the undergraduate students' attitudes towards online counseling were at a high level. Further, the undergraduate students' attitudes towards online counseling were statistically significant differences at a level of p<0.01 attributed to the variables of genders and GPAs.