This report aims to support the work of UNFPA and partners by presenting a background and rationale for engaging men and boys. It illustrates a range of initiatives that have engaged men and boys for the promotion of gender equality as well as sexual and reproductive health and reproductive rights. Based on those experiences that have emerged over the years, it presents a set of lessons learned in the areas of evidence and data on engaging men and boys; research, knowledge, and tools for working with men and boys; advocacy, network and partnership building; support at policy and institutional levels; as well as engaging men and boys at the community and individual levels.