The Accreditation role of the National Universities Commission (NUC) and the quality of the educational inputs into Nigerian university system was investigated in this work, using a descriptive research of survey design. The population consisted of public Universities in South-West, Nigeria. The sample was made up of 300 subjects, consisting of 50 staff members from six Universities sampled from the population. The findings of the study revealed a moderate level of NUC performance of its accreditation role, and a direct positive relationship with quality of inputs into Nigerian university system. Based on the findings of the study, conclusions were drawn and recommendation made that the National Universities Commission should improve on its accreditation role to improve on the quality of educational inputs into Nigeria university system.