This paper examined teachers’ quality and internal efficiency of primary schools in Ekiti State, Nigeria. As an expo facto and descriptive research, the study population comprised all the 694 primary schools in the State. Out of this, a sample of 520 primary schools was selected through the simple random sampling techniques. The headteachers of the 520 primary schools were the respondents in the study. A cohort of 91,061 pupils who entered the schools in 2003 and graduated in 2008 were purposively selected for the study. Two instruments were used to collect data. These were an inventory and a questionnaire. The data collected were analyzed using frequency counts, percentages, Pearson Product Moment Correlation analysis, Correlation Matrix, Regression Analysis of Variance and Multiple Regression. It was found that teacher quality had significant relationship with the internal efficiency of primary schools in the State. The best predictor of internal efficiency of the schools was teacher qualifications. It was then recommended that the State government should intensify more effort in the training of teachers in order to acquire higher qualifications that would enhance the internal efficiency of primary schools in the State.