<p style="text-align:justify">Teachers and teaching styles are two important factors influencing students’ academic performance. In this action research study, we investigated the differential effectiveness of two teaching methods, conventional learning (CL) and peer-cooperative learning (PCL), on students’ academic performance in fractions. A sample of 120 tenth grade mathematics students from Ibadan North Local Government Area of Oyo State in Nigeria was used for the study. The students were selected from three different secondary schools and grouped into two groups: the experimental (PCL) group and the control (CL) group, each having 60 students. A sample of 5 multiple-choice objective and 5 theory test questions titled Fraction Performance Test (FPT) was used to measure their academic performance after the treatment, and the assessment test scores were recorded. Descriptive statistics of the mean were used to answer the research question, while the two-way ANOVA technique was adopted for testing the research hypothesis at an alpha of 0.05. Summarily, the F (3, 116) statistic (= 8.55, <em>p</em> < .001) indicates significant differences in the effectiveness of the teaching methods. The mean scores also reveal that peer-cooperative learning was more effective than the conventional teaching approach. While the former proved to be a more efficacious treatment for female students, the latter was more suitable for male students. We recommend that different approaches be attempted by teachers, and the most effective in overcoming students’ resistance to learning and improving their academic performance be adopted.</p>