The High prevalence of HIV/AIDS can lead to a less in productive age in Indonesia. This problem can be attributed to the risk behavior of school age children, a risk group for HIV/AIDS infection. This study aims to analyse HIV/AIDS prevention factors among junior high school students. The research used a descriptive correlation and a cross sectional approaches. The sampling method employed a purposive sampling at SLTP X in Jakarta whose subjects fulfilled the inclusive criteria. The intrinsic and extrinsic factors were explored. The intrinsic factors,—perception on understanding, attitude, and HIV/AIDS prevention—were significantly correlated with the contagious risk behavior among junior high school students. The extrinsic factors (involving external source of information, information from parents, facilities, information from other people, and community stigma) were significantly correlated with contagious risk behavior among students. Based on this findings, it is imperative to improve knowledge through communication, information, and education on HIV/AIDS prevention factors from contagious risk behavior of junior high school students. It is also important to improve guided supervision and counseling ability from teachers and intensive assistance from parents.