The article describes an international collaboration that systematically reviewed the evidence on financing mechanisms for family planning/contraception, assessed the strength of and summarized the evidence, identified research gaps, and proposed a new research agenda to address the gaps. The review found that the evidence base is weak owing to the paucity of studies, diversity in findings, and variations in intervention, study design, and outcome measures. Of more than 17,000 papers reviewed only 38 met the eligibility criteria. A number of general recommendations on the directions and areas of future research can be drawn. There is a strong need for more robust study designs on the effectiveness of financial incentives in family planning.