Background: The prevalence of risky sexual behavior among adolescents has become a global challenge, contributing to rising rates of sexually transmitted infections, including HIV, gonorrhea, and chlamydia. Multiple factors shape the occurrence and consequences of adolescent sexual behavior. Objective: This study aimed to identify the prevalence and determinants of risky sexual behavior among adolescents. Method: This community-based, cross-sectional study involved 692 adolescents from 15 subdistricts in Manado City, Indonesia. A multistage random sampling method was used. The study included questions on demographic data, knowledge, self-esteem, peer influence, and risky sexual behavior. Data analysis in this study used the chi-square (χ²) test, and hierarchical logistic regression was also conducted to identify factors influencing risky sexual behavior among adolescents. Results: The findings indicate that 32.7% of individuals engaged in risky sexual behaviors. A statistically significant correlation (p<0.05) was observed between risky behavior and variables such as age, gender, access to sexual information, exposure to pornographic films, and peer influence. The most significant predictors of risky sexual behavior included age (OR=1.982, p=0.001) and peer influence (OR=2.883, p=0.01). Conversely, access to sexual information (OR= 3.556, p=0.043 and family size (OR=1.583, p=0.048) were identified as key factors associated with protective behavior. Conclusion: Peer influence, age, and exposure to pornographic films are strongly associated with risky sexual behavior among adolescents and should be carefully considered in developing public health interventions. Moreover, future research should investigate parental perspectives on adolescent risky sexual behavior through qualitative approaches that integrate local cultural values to strengthen evidence-based interventions.