Dynamic mathematics software (DMS) has been used in mathematics education for years. However, there is little research which considers integrating the pedagogy of cooperative learning in the DMS environment. The aim of the study is to investigate, using a quasi-experimental research design, the effect of cooperative learning with DMS on students’ mathematics achievement. Students in experimental group learned the topic of inversely proportional functions cooperatively using DMS while those in control group had typical didactic instruction. Participants were all ninth-grade students in a Macao private school. Participants were administered an achievement test designed by schoolteachers before and after the instruction. Analysis of students’ results on this measure, pre- and post-intervention, showed that the combination of cooperative learning with DMS had a significant influence on students’ mathematics achievement.