Mathematics anxiety and declining intrinsic motivation are persistent challenges in secondary education, driving educators to explore gamification as an engagement strategy.

To examine the effect of gamification on academic motivation and mathematics achievement in secondary school students, and test self-efficacy as a mediating variable.

A quasi-experimental pre-test/post-test design with a control group was implemented across 220 Grade 9 students over one academic semester. Gamification elements (points, badges, leader boards, narrative quests) were embedded in regular instruction.

The experimental group demonstrated significantly higher post-test motivation scores (M = 74.8 vs. 61.3, p < 0.001, Cohen's d = 0.89) and mathematics achievement (M = 72.4 vs. 63.1, p < 0.001). Self-efficacy partially mediated the motivation-achievement relationship (β = 0.31, 95% CI: 0.19–0.44).