Abstract: This study seeks to investigate the extent to which self-esteem plays a mediating role between social media and communication skills among undergraduate students at St. Augustine University of Tanzania, Mwanza Campus. It aims to achieve this by (1)Identifying the extent of the use of social media by undergraduate students (2) Exploring the nature of information shared among undergraduate students in social media (3) Determine the extent of the interrelationship between use of social media and communication skills (4) Examine the extent of the interrelationship between social media and communication skills as moderated by self-esteem (5) Assess whether social class moderates the relationship between self-esteem and communication skills.In view of the background and literature review, it was found that students use and access various kinds of information on social media which influences their self-esteem.