This study aimed at investigating the impact of social media usage on the academic performance of students at Mount Kenya University, Thika Sub-County, Kenya. This study used stratified random sampling technique to select a representative sample of students from the target of students in the undergraduate department of Mt. Kenya University. Data collection for this study was done through administering written questionnaires and also surveying a selected sample of undergraduate students. The data collection method was be based on a quantitative design. The main question at the center of this study was whether the heavy use of Twitter by students has a significant impact on their learning. The second objective of the study focused on investigating the purposes for which students use social media and how these purposes correlatef with their academic outcomes. The results of this research confirmed the need to better understand the social dynamics of the university's social media, including students' unique characteristics. Data collection tools was by use of administering questionnaires and surveys. The data was analyzed quantitatively by use descriptive statistics such as percentages, graphs and pie charts. The findings provided insights into the multifaceted impact of social media on academic performance of students in Mt.kenya university.The findings also confirmed that students who spent more time on internet are likely to have poor grades since they spent most of their time for entertainment purposes,chatting with their friends and also for fun .Likewise,,,, students who spent most of their time on academic purposes arw likely to perform better in their academics.There was a clear indication that social media usage by Mt.Kenya university students affected their academics both positively and negatively.The recommendation of this research was to implement and come up with policies which will help students to balance their social media use and their studies.