This study investigated the developmental influence of collaborative games in the Grade 6 mathematics classroom. Development in areas such as awareness of mathematics, confidence, competence, curiosity, love for mathematics, appreciation of mathematics, creativity, recognition of mathematics, understanding, and knowledge and skills was investigated. The following three data collection methods were used: intervention, observations, and interviews. For the intervention, a quasi-experimental design was used to assign two out of four classes to an experimental group, and the other two to a comparison group. Fifty-one Grade 6 learners participated in the intervention, which covered the following four mathematics topics: multiplication, nets of 3D-objects, symmetry, and division. Each topic included a pre-test and post-test, with learners being observed during the completion of the post-tests. For the posttests, the comparison group completed the textbook activities individually as they usually would. The experimental group completed the same activities, but in a gamebased worksheet format while collaborating in heterogeneous pairs. The results revealed that the experimental group increased 4.28% more from the pretests to the post-tests than the comparison group. This implies that there was a developmental difference, which can be ascribed to the implementation of collaborative game-based worksheets. The Game Object Model, which was the framework used in this study, provided essential information regarding designing educational games that are conducive to learners’ mathematical development. The experimental group increased the most in multiplication and division, which required skills in routine procedures. Low-achieving learners benefited the most from collaborating in heterogeneous pairs in their achievement in mathematics. The experimental group showed a high level of collaboration as they helped each other frequently. A need for support was noted in the comparison group when they asked for assistance from the teacher or a group leader according to the classroom seating arrangements, even though they were instructed to complete the activity individually. Although collaborative games have positively influenced learners’ development in mathematics, observations also show that the teacher plays an important role in learners’ development in mathematics with regard to focus, motivation, and stirring up a love for mathematics in the learners.