This study examined the effects of the guided discovery approach on Senior Secondary Two students’ performance in volumetric analysis. A quasi-experimental design with non-randomized pre-test and post-test groups was adopted. The sample consisted of 98 students selected from two secondary schools using simple random sampling. Data were collected using the Volumetric Analysis Performance Test (VAPT), a researcher-developed instrument designed to assess students’ understanding of acid–base titration. The test comprised six structured essay questions totaling 25 marks, measuring students’ procedural skills, conceptual understanding, and quantitative problem-solving ability in volumetric analysis. The instrument was validated by two experts in chemistry education to ensure alignment with curriculum objectives, while reliability testing using the Kuder–Richardson Formula 20 yielded a coefficient of 0.85. Mean and standard deviation were used to answer the research questions, and Analysis of Covariance (ANCOVA) was employed to test the hypotheses at a 0.05 level of significance. The results revealed a significant difference in the performance of students taught using the guided discovery approach compared to those taught using conventional methods, F(1,95) = 162.407, p < 0.05. No significant difference was observed between male and female students exposed to guided discovery, F(1,47) = 0.135, p > 0.05. The study highlights the significant role of guided discovery in enhancing students’ understanding of volumetric analysis. It provides significant evidence that structured, student-centered instruction improves learning outcomes in complex chemistry topics. The findings have significant implications for science education, particularly in contexts where learners struggle with abstract concepts and practical applications, and offer guidance for teachers, curriculum planners, and policymakers seeking to strengthen chemistry teaching and promote effective learning for all students.