Gender inequality remains a critical challenge and threatens to severely undermine progress towards the new Global Goals for Sustainable Development (SDGs). This continued challenge is recognised in the policies and commitments of various development agencies. But while many gender equality policies and programmes only target and work with women and girls, compelling evidence and experience shows that engaging men and boys in these processes is crucial for lasting change. Drawing on global evidence from the EMERGE programme, this paper explains why better engaging men and boys is crucial, the implications for reframing policy design and implementation, and provides key recommendations for policy.