Globally, there is growing awareness of the important contributions men can make as key stakeholders in maternal and newborn health (MNH), and increased investment in interventions designed to influence men's engagement to improve MNH outcomes. Interventions typically target men, women, couples or health providers, yet how these stakeholders perceive and experience interventions is not well understood and the fact that women may experience these interventions as disempowering has been identified as a major concern. This review aims to synthesise how women, men, and providers perceive and experience interventions designed to influence men's engagement in MNH, in order to identify perceived benefits and risks of participating in interventions, and other key factors affecting uptake of and adherence to interventions. We conducted a qualitative evidence synthesis based on a systematic search of the literature, analysing a purposive sample of 66 out of 144 included studies to enable rich synthesis. Women, men and providers report that interventions enable more and better care for women, newborns and men, and strengthen family relationships between the newborn, father and mother. At the same time, stakeholders report that poorly designed or implemented interventions carry risks of harm, including constraining some women's access to MNH services and compounding negative impacts of existing gender inequalities. Limited health system capacity to deliver men-friendly MNH services, and pervasive gender inequality, can limit the accessibility and acceptability of interventions. Sociodemographic factors, household needs, and peer networks can influence how men choose to support MNH, and may affect demand for and adherence to interventions. Overall, perceived benefits of interventions designed to influence men's engagement in MNH are compelling, reported risks of harm are likely manageable through careful implementation, and there is clear evidence of demand from women and men, and some providers, for increased opportunities and support for men to engage in MNH.