The enhancement of the academic achievement of the Nigerian students has continued to engage the attention of educational practitioners and policy makers. This paper investigated institutional factors as predictors of students' academic performance in Colleges of Education in South-Western Nigeria. The study employed the ex post facto design using a survey design and a multiple regression model. The samples used for the study consisted of 1,100 (200 and 300 levels) National Certificate of Education (NCE) students in Federal, State and Private NCE-awarding institutions in South Western Nigeria, using stratified sampling techniques. The validated research instruments used for the study had the following psychometric properties: Cronbach alpha (a) [0.79 (students) and 0.73 (lecturers); Guttman split-half 0.78 (students) and 0.71 (lecturers; and Spearman-Brown equal length results were 0.69 (students) and 0.70 lecturers)]. The study found that a number of institutional factors: student-teacher-ratio, lecturers' interest and commitment, school calendar stability and to a lesser extent, teaching method, were significant predictors of students' academic achievement in the colleges of education sampled. On the other hand, school leadership, school plant and library facilities were not found to be significant predictors of academic achievement. The study proffered a number of recommendations to improve the quality of educational policy outcomes geared towards improving students' educational performance and hence enhance the achievement of national economics goals.