Objective: To assess the awareness of contraceptive methods, understanding of HIV/AIDS prevention and the perception of HIV/AIDS risks among secondary school students in Tanzania.Methods: An anonymous self-administered questionnaire survey was conducted among secondary school students in Tanzania. The questionnaire included sociodemographic characteristics, awareness of contraceptive methods, an understanding of HIV/AIDS prevention, and the perception of HIV/AIDS risks. Three secondary schools were selected by considering the gender balance and location, which included the urban and surrounding areas. The research objectives, methods, and ethical considerations were explained, and the students voluntarily completed the questionnaire.Results: A total of 233 responses were collected, and 204 responses were considered valid for the analysis. The mean and standard deviation of age were 18.5 ± 1.0. Regardless of the gender, age, religion, and major course of study, the maternal educational status (adjusted odds ratio [AOR]: 3.129; 95% confidence interval [CI]: 1.324, 7.398; P=0.009) and the number of information sources (AOR: 7.023, 95% CI: 3.166, 15.579, P<0.001) demonstrated associations with the awareness of contraceptive methods. Respondents who lived outside a dormitory (AOR: 3.782; 95% CI: 1.650, 8.671; P=0.002) and who currently had a partner (AOR: 3.616; 95% CI: 1.486, 8.800; P=0.005) were associated with a high level of understanding of HIV/AIDS prevention regardless of gender, age, religion, and major course of study. Respondents with few information sources were associated with a high level of perception of HIV/AIDS risks (AOR: 0.293; 95% CI: 0.115, 0.747; P=0.010), regardless of gender, age, religion, and major course of study.Conclusion: Factors associated with the awareness of contraceptive methods, the understanding of HIV/AIDS prevention, and perception of HIV/AIDS risks were not consistent. To ensure the improvement of these factors among secondary school students, sexual health education should be integrated into educational programs and provided holistically.