In the evolving landscape of education, creative ways to improve student engagement and academic performance are being investigated more and more. Because traditional teaching approaches frequently fail to hold students' attention, educators are forced to look for substitutes that can create a more dynamic and engaged learning environment. Amidst this change, there has been an increase in interest in methods that enhance academic performance while also making learning fun. This study looks into the effects of game-based learning on the academic achievement of Grade 8 students in Mathematics at the University of La Salette High School. Employing a Quasi-experimental design, specifically the pretest-posttest control group design was adopted using two intact groups. A total of 79 students, divided into control (38 students) and experimental (41 students) groups, participated in the study. The control group received instruction through traditional teaching methods such as board works, seat works, assignments and weekly quiz, while the experimental group engaged in various teacher-made, non-digital mathematical games such as games such as Probability Trio: A Three-Game Challenge, Case Quest: The Million Peso Challenge derived from deal or no deal gameshow, Card Category Conundrum, a card game activity and more activities. The main instrument used in this research is a 50-item researcher-made Mathematics Achievement Test. The test underwent a series of steps of validation and the reliability coefficient was also determined (KR-20 = 0.9141). Statistical analysis included paired samples t-tests, independent t-tests, and Cohen’s D to determine significant differences in mean scores and the effect size of the game-based strategy. Results indicated that both groups showed progress from their pretest to posttest scores; however, the experimental group demonstrated a significantly higher average gain of 7.1 compared to the control group's gain of 3. This suggests that game-based learning positively impacts students' mathematical achievement. Pretest scores were comparable between groups, but posttest results revealed a substantial difference favoring the experimental group. The findings highlight the effectiveness of game-based learning in improving academic achievement, with a large effect size indicated by Cohen's D. In light of these findings, the study recommends that mathematics educators integrate game-based activities into their instruction to enhance student performance and confidence in Mathematics. Continuous updating of activities, curriculum development that incorporates game-based learning, and professional development for educators are also advised. Engaging parents in supporting game-based learning at home and conducting further research with larger sample sizes to explore digital game effects are suggested for future studies.