"Social media sites allow students particularly in tertiary institutions to adopt different types of social networking sites to interact; keep in touch with their families and friends and keep up with their academic assignments. Conversely, there has been a growing concern that students at the tertiary level in Nigeria have devoted much of their time to communication through social networking sites at the expense of serious academic work. Thus, the study investigated how the undergraduate students of the University of Port Harcourt, Nigeria make use of social media sites for academic purposes. It also examined how much time the students allotted to socialisation and academic work in the use of online media. Anchored on the Uses and Gratification Theory, the survey research design was adopted while questionnaire was used as the instrument of data collections. Data were generated from a sample of 600 respondents randomly selected from six faculties from the University of Port Harcourt, Nigeria. Findings showed that most undergraduate students devoted more time to social networking sites mainly for socialisation and only used the sites for academic purposes when they were given assignments or when researching on a particular topic. The findings also revealed that the length of time spent on social networking sites socialising reduced the respondents’ ability to concentrate on academic work and eventually led to poor performance of undergraduate students. Based on the findings and conclusion, it was recommended among others, that media literacy education as a course should be introduced and integrated into the tertiary institutions’ progammes, especially at the undergraduate level." (Abstract)