This study investigated the level of job satisfaction and its influence on personnel commitment in university libraries in South–West, Nigeria. The study used descriptive survey research design. The population of the study comprised of 1,163 participants from public and private university libraries in South–West, Nigeria, out of which 643 participants were sampled using a multistage sampling technique. A structured questionnaire was used to collect data. A total of 643 copies of the questionnaire were administered, out of which 541 copies, representing 84.1%, were retrieved and analysed. Data collected were presented and analysed using both descriptive and inferential statistics. Mean, percentage, and standard deviation were used to analysed research questions, while regression analysis was used for the hypothesis. Results indicated that the level of job satisfaction was high in terms of the nature of work (M = 3.87), opportunities for promotion (M = 3.30), supervision (M = 3.14), and communication flow (M = 3.45). Also, the results revealed that job satisfaction significantly influenced personnel commitment in university libraries (p≤0.05). The study concluded that job satisfaction predicts personnel commitment in the region. Based on the conclusion, the study recommended that university policy makers should prioritise equitable remuneration and work environment for library personnel to sustain commitment and professional engagement.