This study examined the relationship between teachers’ continuing professional development (CPD) and students’ academic performance in senior secondary schools in South-South Nigeria. The study was guided by seven research questions and seven null hypotheses. A correlational survey and ex-post facto research design were adopted. From a population of 84,841 teachers across 709 public senior secondary schools, a sample of 382 teachers from 71 schools in Edo and Delta States was selected using a multistage sampling technique. Two instruments—Teachers’ Continuing Professional Development Questionnaire (TCPDQ) and Students’ Academic Performance Proforma (SAPP)—were used for data collection. The reliability of TCPDQ was established through the split-half method, yielding a coefficient of 0.84. Data were analyzed using descriptive statistics (mean and standard deviation) for research questions and inferential statistics (linear and multiple regression) to test hypotheses at the 0.05 significance level. Findings revealed a high extent of teachers’ CPD and very good students’ performance in the Senior School Certificate Examination (SSCE) from 2013 to 2022. A significant relationship was found between teachers’ CPD and students’ academic performance. The study concluded that enhancing teachers’ professional development positively impacts students' academic outcomes. It was recommended, among others, that school principals should support teachers in pursuing further qualifications relevant to their subject areas. This would equip them with the pedagogical skills, knowledge, values, and attitudes necessaryforeffectivecurriculum implementation and improved student performance in public senior secondary schools in South-South Nigeria