This study investigated whether students’ performance in Basic Science in the Basic Education Certificate Examination (BECE) predicts their performance in Chemistry in the Senior Secondary Certificate Examination (SSCE) within the Vandeikya Education Zone. The study was guided by three research questions and three null hypotheses. An ex-post facto research design was employed. The population consisted of 4,875 students, while the sample comprised 488 Basic Science students from the 2021 cohort and 488 Chemistry students from the 2024 cohort, all with complete and verifiable examination records.

An inventory developed by the researchers was used to systematically extract and organize performance data, serving as the primary instrument for data collection. Regression analysis was conducted to answer the research questions and test the hypotheses at the 0.05 level of significance. Results revealed that performance in Basic Science significantly predicted students’ performance in Chemistry at the SSCE level, accounting for 48.0% of the variance (F(1, 486) = 145.415, p < 0.05). For male students, Basic Science performance predicted 38.0% of the variance in Chemistry scores (F(1, 242) = 40.894, p < 0.05), while for female students, the predictive power was even stronger at 55.9% (F(1, 242) = 109.973, p < 0.05). Based on these findings, it was recommended that teachers and schools should prioritize strengthening Basic Science instruction at the junior secondary level to provide a solid foundation for students’ future success in Chemistry and other science subjects. Educators and policymakers should also utilize BECE Basic Science results to identify students at risk of underperformance and implement targeted academic support and interventions prior to their progression to senior secondary school.