The present study quantitatively examines the relationship between the effects of academic workload to the perceived mental fatigue of undergraduate college students from Mapúa University in the Philippines. The current global pandemic and the abrupt shift from face-to-face classes to remote learning affected the students' mental health. The researchers used data from a sample of 104 respondents obtained from a digital survey containing the Fatigue Assessment Scale and NASA-Task Load Index, which was then analyzed using descriptive and inferential statistics. Results presented a strong relationship between the academic workload factors during online classes and students' overall mental fatigue level. Thus, results show that these factors significantly contribute to the intensity of the mental fatigue of college students. Based on the conclusion, the results show that the FAS is greatly affected by each dimension – mentally or physically. In addition, the academic workload assigned to each respondent shows that all cognitive factors such as mental demand, physical demand, temporal demand, effort, and frustration are significantly affected due to the assigned workload to the students during an online class. Thus, resulting to students must exert more mental effort to accomplish required outputs.The present study quantitatively examines the relationship between the effects of academic workload to the perceived mental fatigue of undergraduate college students from Mapúa University in the Philippines. The current global pandemic and the abrupt shift from face-to-face classes to remote learning affected the students' mental health. The researchers used data from a sample of 104 respondents obtained from a digital survey containing the Fatigue Assessment Scale and NASA-Task Load Index, which was then analyzed using descriptive and inferential statistics. Results presented a strong relationship between the academic workload factors during online classes and students' overall mental fatigue level. Thus, results show that these factors significantly contribute to the intensity of the mental fatigue of college students. Based on the conclusion, the results show that the FAS is greatly affected by each dimension – mentally or physically. In addition, the academic workload assigned to each respondent shows that all cognitive factors such as mental demand, physical demand, temporal demand, effort, and frustration are significantly affected due to the assigned workload to the students during an online class. Thus, resulting to students must exert more mental effort to accomplish required outputs.