This study investigated teachers’ professional commitment as a predictor of students’ academic performance in public senior secondary schools in South West Nigeria. The study was guided by two research questions and one null hypothesis. A correlational survey and ex-post facto research design were employed to determine the predictive influence of teachers’ commitment on students’ academic outcomes. From a population of 134 public senior secondary schools and their principals, a sample of 67 schools and 67 principals was selected from Ondo, Osun, and Ogun States through a multistage sampling procedure. Two researcher-developed instruments titled Teachers’ Professional Commitment Questionnaire (TPCQ) and Students’ Academic Performance Proforma (SAPP) were used for data collection. The reliability coefficient of the TPCQ was 0.83, obtained using the split-half method, Pearson Product Moment Correlation, and Spearman Brown Prophecy Formula. Descriptive statistics such as mean and standard deviation were used to answer the research questions, while multiple regression analysis tested the null hypothesis at the 0.05 level of significance.The findings revealed a high level of teachers’ professional commitment and a positive trend in students’ academic performance in Senior School Certificate Examination (SSCE) results from 2013 to 2022. The study concluded that teachers’ professional commitment significantly predicts students’ academic performance in public senior secondary schools in South West Nigeria. It was therefore recommended that State Post-Primary Education Boards in Ondo, Osun, and Ogun States should improve the remuneration and welfare of teachers to enhance their professional commitment. Additionally, school administrators and teachers should set high academic expectations for students and continuously monitor their progress during instructional and assessment activities to foster sustained academic excellence.