This study investigated self-concept as correlate of service delivery of librarians in selected academic libraries in Oyo State. Descriptive survey design was adopted and a sample of 52 librarians were selected by using total enumeration sampling technique. A self-developed questionnaire was used to collect data from 52 respondents, out of which 53 copies of the questionnaire were completely filled and returned. Data collected for the three research questions were analyzed by using frequency counts, percentages and mean while Pearson Product Moment Correlation (PPMC) was used to test the null hypothesis of the study. The study found that the level of service delivery of the respondents was high. The results further showed that the level of self-concept of the respondents was high. Also, the results revealed that insufficient management support for professional development, inadequate training opportunities, poor working conditions, and lack of modern resources are some of the challenges that affect the effective service delivery of the respondents. The results of the hypothesis confirmed that there is a significant relationship between self-concept and service delivery of the librarians. The study recommends that library management should invest in professional development programs that will enhance librarians' skills and knowledge such as regular workshops, seminars, and training on modern library practices, digital resources, and ICT tools which will in turn empower librarians, boosting their confidence and self-concept.