The primary focus of this article is to determine which risk and protective factors are most important to adolescent reproductive health in developing countries. A comprehensive and systematic literature search was conducted on studies that examined factors in relation to the following outcomes: ever had premarital sex, condom use, pregnancy, early childbearing, sexually transmitted infections, and HIV. While the search identified over 11,000 publications, only 61 were retained for the final analysis. The results show that factors which were significantly associated to the outcomes were primarily related to the adolescents themselves. In fact, very few factors outside the individual were found to be related to sexual risk behaviours. This contrasts to similar research conducted among youth samples in the US. While this review confirms the strong need for a broader research base on the risk and protective factors related to adolescent sexual and reproductive health in developing countries, it also does identify key factors that can be addressed through innovative programmes and policies to help improve adolescent reproductive health in the developing world.