Evaluation of website usability is very essential to ensure good use and access to the content of the website. The study assessed the usability of library websites in Universities in South-South Nigeria. Eleven University library websites were identified and examined for the study. The study used an analytical survey method to collect data. A usability checklist was adopted for the study. The checklist has five usability attributes usefulness, Efficiency, Effectiveness, Learnability, and Accessibility. Result shows that six of the eleven University Library websites examined have a total usability score of 50% and above. One library website obtained the highest usability score at 89.5% and the lowest score was 26.3%. Summary of usability attributes of the University Library Websites shows that only five of the eleven websites scored above 50% in terms of site usefulness. For website efficiency, six out of the eleven websites scored 50% and above. For effectiveness only one library website scored 100%; others scored below 50%. All the library websites scored above 50% for learnability except one which scored 33.3%. All library websites scored 50% and above for accessibility. The study concludes that regular evaluation of a library website is core to maintaining the library‘s ability to fulfill support users in the pursuit of their academic and professional goals and also to compete successfully with other standard academic websites.