This study aimed to determine the factors affecting the retention of basic concepts in Mathematics and their relationship to the academic performance of Grade 10 students at Santiago City National High School for the School Year 2025–2026. A descriptive-correlational research design was utilized, involving 270 student-respondents selected through simple random sampling. Data were gathered using a validated questionnaire assessing motivation, goal setting, personalized learning, teaching methods, and availability of resources. Statistical tools such as mean and Pearson r correlation were used for data analysis. The findings revealed that all factors affecting retention motivation, goal setting, personalized learning, teaching methods, and availability of resources were rated high and interpreted as frequently observed among students. Among these, teaching methods obtained the highest mean, indicating that effective instructional strategies play a crucial role in enhancing students’ retention of mathematical concepts. In terms of academic performance, the majority of students achieved very satisfactory to outstanding levels, with no student falling below the passing mark. Furthermore, the results showed that only selected indicators under motivation, goal setting, personalized learning, and teaching methods had a significant relationship with students’ academic performance, although the correlations were generally weak. Meanwhile, most indicators, including those related to the availability of resources, showed no significant relationship, suggesting that these factors alone do not directly influence students’ Mathematics performance. The study concludes that while multiple factors contribute to the retention of basic mathematical concepts, only specific elements such as active participation, goal-oriented behavior, individual effort, and selected teaching strategies significantly affect academic achievement. Hence, it is recommended that teachers strengthen motivational strategies, effective teaching practices, and student-centered approaches, while ensuring the strategic use of resources to enhance retention and improve academic performance.