This guideline provides global, evidence-informed recommendations on protection, promotion and support of optimal breastfeeding in facilities providing maternity and newborn services, as a public health intervention. It is intended to contribute to discussions among stakeholders when selecting or prioritizing appropriate actions in their efforts to achieve the Sustainable Development Goals and the global targets for 2025 as put forward in the Comprehensive implementation plan on maternal, infant and young child nutrition, endorsed by the Sixty-fifth World Health Assembly in 2012, in resolution WHA65.6, the Global strategy for women’s, children’s, and adolescents’ health (2016–2030), and the Global Strategy for infant and young child feeding. The document presents the key recommendations, a summary of the supporting evidence and a description of the considerations that contributed to the deliberations and consensus decision-making.