This study investigated social media usage and library engagement of academic community in selected tertiary institutions in South-East, Nigeria. Three research questions guided the study. The descriptive survey research design was used for this study. The population of the study consisted of all the 161 academic librarians in the five Federal universities in South-East Nigeria. The entire population of 161 academic libraries was used as the sample size. A structured validated questionnaire titled “Questionnaire on Social Media Usage and Library Engagement” (QSMULE) was used for data collection. The questionnaire was subjected to reliability testing using Cronbach Alpha Method. This method was used to test the internal consistency and an overall coefficient of 0.78 was obtained. Frequency counts and percentages was used to answer research question one while descriptive statistics of mean and standard deviation was used to answer the research question two and three. The finding revealed that social media platforms mostly used by the academic community for library-related activities are WhatsApp, Facebook, Instagram, Twitter, LinkedIn and Telegram while those rarely in use include YouTube and Blogs. It was also found that while academic librarians acknowledge the significant benefits of using social media such as improved communication, wider reach, and enhanced service visibility they also unanimously recognize the challenges, including poor infrastructure, inadequate training, and lack of institutional support. Based on the findings, it was recommended amongst others that regular workshops and hands-on training programmes should be organized for librarians to improve their digital literacy and social media competencies. Such initiatives will empower them to use various platforms effectively for service promotion, user interaction, and information dissemination.