METHODS: We conducted a search of electronic databases and gray literature and evaluated the methodological quality and risk of bias of included studies.

RESULTS: A total of 30 studies met the inclusion criteria. Interventions that support girls' schooling through cash or in-kind transfers show the clearest pattern of success in preventing child marriage, with 8 of 10 medium-high quality studies showing positive results. Although limited in number, five studies on favorable job markets and targeted life skills and livelihoods training show consistent positive results. Comparatively, asset or cash transfers conditional on delaying marriage show success only among two of four evaluations, and the three studies on unconditional cash transfers for poverty mitigation show no effect. Findings also show a low success rate for multicomponent interventions with positive results in only one of eight medium-high quality studies. Further, single component interventions were much more likely to be at scale and sustainable than multicomponent interventions.