The aim of this study was to determine the effectiveness of a social marketing approach in reduction of unintended teenage pregnancies. We identified studies undertaken between 1990 and 2008 through electronic searches of databases, manual searches of bibliographies, and consultations with experts. Twelve studies that met the inclusion criteria were selected for further analysis. Results showed variation in intervention effects across specified outcomes (reduction in unintended pregnancies, delayed sexual initiation, contraceptive use at last intercourse, knowledge of contraception and reproductive health, and self-efficacy to refuse unwanted sex). Of the 12 studies, 9 reported significant effects on at least one of the outcomes. Long-term interventions were generally more effective than short-term ones for most outcomes. The impact on male participants sexual behavior was minimal in most studies. Overall, social marketing appears to be an effective approach in reducing teenage pregnancies and influencing sexual behavior change, but the evidence is limited to particular outcomes and context. There is, therefore, need for more primary studies specifically designed around social marketing principles for more robust evaluations. The minimal impact on male participants behavior also warrants further investigation.