This article reviews 23 child marriage prevention programs carried out in low-income countries and employing a range of programmatic approaches and evaluation strategies. We document the types of child marriage programs that have been implemented, assess how they have been evaluated, describe the main limitations of these evaluations, summarize the evaluation results, and make recommendations to improve future prevention efforts. The evidence suggests that programs offering incentives and attempting to empower girls can be effective in preventing child marriage and can foster change relatively quickly. Methodological limitations of the reviewed studies, however, underscore that more needs to be learned about how the programs prevent child marriage and whether impact is sustained beyond program implementation.