Problem Statement: Gender differences in the effects of group learning play a contested role in mathematics education. Several researchers concluded that male students perform better on mathematics than female students. Whilst on the other hand, others reported that female students perform best under the group learning setting whereas the male students perform best in the conventional teaching environment. Consequently investigating gender differences on students' mathematics performance is our main focus. Purpose of Study: The aim of this research was to identify the male and female students' performance with the integration of progressive series of group learning on mathematics achievement in selected rural secondary schools in Bangladesh. The focus of this study is to examine gender-related differences on mathematics achievement of 9th grade students. Methods: The quasi-experimental equivalent pre-post test control group design comprising an experimental group (n = 84) with group learning treatment whilst a control group (n = 84) was given conventional teaching for duration of 15-week. The independent-sample t-test was used to compare the effects of group learning between experimental and control groups, and to examine the gender-related differences in achievement with group students. The MANOVA with repeated measures was employed to determine the main and interaction effects of group learning on test-time and achievement. Findings and Results: The results showed a significant effect of group learning on mathematics achievement and a significant effect on gender-related differences on mathematics achievement. The findings revealed that the group learning students outperformed the conventional students, and both the male and female students in the experimental group improved their mathematics achievement in which the performance of female students were significantly better than that of male students after group learning treatment. Conclusions and Recommendations: Group learning had significant effects on students' mathematics achievement. Gender-related differences with the effects of group learning in terms of mathematics achievement was also significant. Overall performance of both the male and female students was significant while female students outperformed male students in the experimental group after group learning intervention. As such it can be concluded that group learning enhanced mathematics achievement for female students, whilst the male counterparts do not benefit as much as the female group. Thus it is important that female students be provided with opportunities to learn mathematics in the classroom in the group learning environment. Therefore, group learning may be a tool that can be professionally implemented to develop female students' performance in Bangladesh.