This study examined the effect of student-teacher ratio on the academic performance of the primary school students in Odeda Local Government Area of Ogun State. Descriptive survey research design using 118 randomly selected primary school teachers was employed for this study. The research instruments encompassed a structured questionnaire addressing the socio-demographic and a secondary data of the students’ academic performance. Descriptive statistics was used to analyse the demographic data while simple linear regression was applied to test the two formulated hypotheses at 0.05 level of significance. Results showed that there is a significant effect of student-teacher ratio and the academic performance (t = 7.786, p<0 xss=removed xss=removed xss=removed xss=removed xss=removed xss=removed>0.05). It was therefore, recommended among others, that the State Educational Planners and Policy Makers pay prompt attention to this student – teacher issue, and as well take drastic measures of improving the student-teacher ratio by adopting synergic relationship of both educational administrators and Parent-Teachers Association body in employing more competent teachers for better students’ academic performance.