BACKGROUND AND OBJECTIVES: Few women in industrialized countries achieve the World Health Organization's recommendation to breastfeed exclusively for 6 months. Governments are increasingly seeking new interventions to address this problem, including the use of incentives. The goal of this study was to assess the evidence regarding the effectiveness of incentive interventions, delivered within or outside of health care settings, to individuals and/or their families seeking to increase and sustain breastfeeding in the first 6 months after birth. METHODS: Searches of electronic databases, reference lists, and grey literature were conducted to identify relevant reports of published, unpublished, and ongoing studies. All study designs published in English, which met our definition of incentives and that were from a developed country, were eligible for inclusion. Abstract and full-text article review with sequential data extraction were conducted by 2 independent authors. RESULTS: Sixteen full reports were included in the review. The majority evaluated multicomponent interventions of varying frequency, intensity, and duration. Incentives involved providing access to breast pumps, gifts, vouchers, money, food packages, and help with household tasks, but little consensus in findings was revealed. The lack of high-quality, randomized controlled trials identified by this review and the multicomponent nature of the interventions prohibited meta-analysis. CONCLUSIONS: This review found that the overall effect of providing incentives for breastfeeding compared with no incentives is unclear due to study heterogeneity and the variation in study quality. Further evidence on breastfeeding incentives offered to women is required to understand the possible effects of these interventions.