This study determined the difficulties and errors of Grade 9 learners in solving quadratic equations, it gauged the developmental of strategic intervention material. The researcher used the descriptive-developmental research design and used the 45 Grade 9 learners as respondents. Researcher-made test was used to gather the needed data. Frequency count, percentage, and mean were the statistical tools used. The results of the study showed that Grade 9 learners performed fairly satisfactory in characterizes the roots of quadratic equation using the discriminant, describes the relationship between the coefficients and the roots of a quadratic equation, solves equations transformable to quadratic equations (including rational algebraic equations), solves problems involving quadratic equations and rational algebraic equations, illustrates quadratic inequalities, solves quadratic inequalities, and solves problems involving quadratic inequalities. Additionally, the Grade 9 learners commit more errors in the reading errors and comprehension error. Further, the developed Strategic Intervention Materials on Solving Quadratic Equation for Mathematics 9 is very highly valid. Based from the findings, the following conclusions were drawn: The Grade 9 learners often encounter reading errors when solving quadratic equations, suggesting they have trouble comprehending the problem statements. This issue highlights a fundamental barrier to their mathematical proficiency. Additionally, they face specific challenges in areas such as characterizing the roots of equations, solving equations that can be transformed, and understanding quadratic inequalities, which are critical skills for mastering quadratic equations. To address these difficulties, strategic intervention material has been shown to be highly effective. These materials provide targeted support and practice, significantly improving the learners’ abilities to solve quadratic equations and enhancing their overall mathematical competence. It is therefore recommended that teachers use effective instructional strategies, including clear explanations, diverse problem-solving approaches, and real-world examples, to improve learners’ understanding and proficiency in quadratic equations. Learners should actively participate in problem-solving activities, seek help when needed, practice regularly, and develop a strong foundation in basic skills. The use of strategic intervention materials for teaching quadratic equations in Grade 9 is advised to enhance learners’ problem-solving competencies, and they study’s finding should be discussed in school Learning Action Cell (LAC) sessions. Future research should investigate the specific causes of learners’ difficulties, explore additional interventions and instructional approaches, and examine the long-term effects on learners’ mastery of quadratic equations, as well as the potential benefits of technology integration and gamification in teaching quadratic equations.