The study examined manpower determination and academic staff job performance in Nigeria universities. It looked at how manpower determination is related to the performance of academic staff in Nigerian Universities. The descriptive survey design was used for this study. The population of the study consisted of 154 Deans, 849 Heads of Department and 11,828 academic staff in Southwest Nigeria Universities. The sample was one thousand eight hundred (1,800) respondents, comprising 20 Deans, 70 Heads of Department and 1,710 academic staff.