This chapter focuses on efforts to engage men and boys in preventing gender-based violence (GBV). We examine violence prevention efforts at the individual, family, community, and global levels. We highlight a range of innovative approaches from around the world, including restorative justice practices, online programs, culturally focused counseling, working with fathers and their children to recognize and prevent intergenerational violence, enhancing men’s capacity to support their pregnant partners, and involving men as allies in the effort to prevent violence against women.