Violence perpetrated by and against men and boys is a major public health problem. Although individual men’s use of
violence diff ers, engagement of all men and boys in action to prevent violence against women and girls is essential. We
discuss why this engagement approach is theoretically important and how prevention interventions have developed
from treating men simply as perpetrators of violence against women and girls or as allies of women in its prevention,
to approaches that seek to transform the relations, social norms, and systems that sustain gender inequality and
violence. We review evidence of intervention eff ectiveness in the reduction of violence or its risk factors, features
commonly seen in more eff ective interventions, and how strong evidence-based interventions can be developed with
more robust use of theory. Future interventions should emphasise work with both men and boys and women and girls
to change social norms on gender relations, and need to appropriately accommodate the diff erences between men and
women in the design of programmes.