<p>Adolescence is a critical phase in life characterized by decisions on health-risk sexual behaviors. Oftentimes, most adolescents are not adequately prepared regarding their sexual lives and may experience a power imbalance in sexual relationships. This exposes them to sexually transmitted diseases, sexual coercion, abuse, exploitation with an unplanned pregnancy, out-of-school and early marriage as possible outcomes. Sex education then, becomes a crucial systematic development program that propels safe maturation. Our qualitative study explored the concerns of parents and teachers about understanding safe sex through school-based comprehensive sex education for adolescents in secondary schools. Data was elicited from 36 parents and three biology head teachers in three selected public schools through focus group discussions and in-depth interviews. Findings revealed that sexual promiscuity prevails among adolescents in secondary schools. Though some were lured, others participated willingly out of exploitation. Participants advocated for school-based sex education, to complement traditionally accepted sexual abstinence as a measure to safeguard the health and social well-being of adolescents. Participants’ concerns about obtaining comprehensive sexual knowledge through academic institutions included issues such as adolescent age, gender, fear of promiscuity and cultural values. Participants evidence-based interventions focused on professional groups collaborating with schools to provide comprehensive reproductive healthcare knowledge. The study recommends collaboration of stakeholders and social workers, to increase efforts to primarily ensure sexual abstinence and knowledge of safe sex among adolescents in academic institutions through comprehensive sex education in Nigeria.</p>