In light of the social consequences of early childbearing, unplanned pregnancy, and the transmission of AIDS, a great need exists to understand how adolescents make sexual and reproductive decisions. Drawing primarily on literature from sub-Saharan Africa, this article focuses on three behavioral outcomes: nonmarital sexual activity, contraceptive use, and condom use. It explores adolescent's perceptions of the costs and benefits of engaging in these behaviors, their assessment of their susceptibility to the potential consequences of their actions, and the role of family, peer, and dyadic factors in shaping their reproductive decisions. The literature reveals that cultural values regarding sexuality and gender roles, the power dimensions of adolescents' lives, and economic disadvantage exert powerful influences on the decisionmaking process. Decisions to engage in unprotected sex may also be based on insufficient knowledge and distorted judgements of the risks of becoming pregnant and acquiring sexually transmitted infections. Nondecisionmaking is found to be fairly common in some contexts.