This study explored students’ knowledge and perceptions of sex education at Rizal National High School. Employing a descriptive-quantitative approach, data were gathered from 60 students across Grades 7 to 12. The findings revealed an average level of knowledge on sex education but significant gaps in family-based discussions and access to contraceptive knowledge. While students recognized the importance of sex education in informed decision-making, cultural norms, stigma, and inadequate teacher training limited its effectiveness. Notably, the study highlighted the need for a culturally tailored teaching plan grounded in Constructivist and Social Learning Theories. The proposed teaching plan integrates participatory methods and multimedia tools to foster inclusivity and reduce stigma. Recommendations include parental workshops, professional training for educators, and partnerships with health professionals to enhance delivery. This study underscores the importance of comprehensive reproductive health education in addressing teenage pregnancies and improving sexual health outcomes.