We reviewed existing literature on private sector initiatives that have shown effectiveness in improving maternal and neonatal health. The private sector constitutes a significant proportion of delivery services for women in developing countries and it also plays a key role in family planning, abortion, nutrition, and antenatal care. We primarily address maternal health outcomes and include interventions that improve neonatal health outcomes where they are included in the study design or interventional strategy alongside maternal outcomes. We do not review evidence that addresses neonatal outcomes alone, as this would go beyond the scope of this paper.