This study examines the mediating effect of sports engagement on the relationship between metacognition and mathematics self-efficacy among 304 Grade 10 students in Lupon, Davao Oriental. Using a predictive-explanatory research design and stratified random sampling, data were gathered through a validated survey questionnaire and analyzed using correlation and mediation analyses. The findings revealed high levels of metacognition (M = 2.89), sports engagement (M = 3.05), and mathematics self-efficacy (M = 3.03). Correlation analysis indicated significant positive relationships between metacognition and mathematics self efficacy (r = .59, p < .05), metacognition and sports engagement (r = .50, p < .05), and sports engagement and mathematics self-efficacy (r = .47, p < .05). Mediation analysis further revealed significant total (β = .72, p < .05), direct (β = .58, p < .05), and indirect effects (β = .14, p < .05), indicating that sports engagement partially mediates the relationship between metacognition and mathematics self-efficacy. Grounded in Social Cognitive Theory, the findings suggest that students with higher metacognitive abilities tend to exhibit greater sports engagement and stronger mathematics self-efficacy. The study highlights the importance of strengthening metacognitive skills and promoting sports participation as complementary strategies for enhancing students' confidence and performance in mathematics.