This paper provides a critical assessment of efforts to involve men in the prevention of men's violence against women. Although there is a substantial evidence base attesting to the effectiveness of at least some strategies and interventions, this field is also limited in important ways. Violence prevention efforts often have focused on changing men's attitudes, rather than also seeking to transform structural and institutional inequalities. While feminist and queer scholarship has explored diversities and pluralities in the organisation of sexuality, much violence prevention work often assumes a homogenously heterosexual male constituency. Too often this work is conceptually simplistic with regard to gender. Against this background, this paper contests and complicates several assumptions that are part of an emerging consensus in men's violence prevention: first, that it is in men's interests to support progress towards non-violence and gender equality; second, that the best people to engage and work with men are other men; and finally, the strengths and limitations of inviting and drawing on ‘real men’. A critical assessment of the field's working assumptions is vital if it is to contribute to the future prevention of men's violence against women.