Employees’ job satisfaction is essential to the accomplishment of organizational aims and objectives. Indeed, employee satisfaction is a key indicator of organisational effectiveness; same narrative can be said of the university libraries. This study investigated leadership styles as factor influencing job satisfaction of library personnel in university libraries in Ondo State. The population of the study was one hundred and twenty (120) librarians and library officers in eight (8) university libraries in Ondo State. The instrument for this research work was structured questionnaire. Frequencies, percentages, mean, standard deviation and Pearson Moment Correlation Analysis were used to analyse data using Statistical Package for the Social Sciences (SPSS). The study revealed that respondents were satisfy with their job. Response on democratic leadership style indicates that respondents agreed that staff’s work were checked on a regular basis to assess their progress and periodic meetings were always been held to show support for library policy and mission. The findings of the study revealed a significant relationship between leadership styles and job satisfaction among university library personnel in Ondo State. It was recommended that university managements should treat all academic staff equally and ensure there is no marginalization of any staff in order. Also, leadership style(s) in university library should reflect the values and philosophies of the institution, hence, managers should adopt the most appropriate leadership for any given situation. The library environment is unique, therefore library managers must adopt leadership styles capable of motivating, unify and energise all library personnel towards the achievement of the objectives of the library.