This thesis engages with debates about men’s relationship to feminism through exploring the practice of mixed-gender feminist activism. It focuses on contemporary mixed-gender feminist groups in England and includes four case studies: a feminist discussion group, a student union women’s committee, a DIY (do-it-yourself) collective, and a feminist activist group. These groups were studied using a qualitative case study approach, drawing on data from participant observation, interviews and documents. The thesis explores the groups’ political practices, internal dynamics and feminist beliefs. It highlights the diversity in the groups’ experiences, suggesting that the effects of men’s involvement in feminist groups are varied and context-specific. It also situates the groups within a wider context, showing how they are influenced by existing feminist ideas and other discourses such as the critical study of men and masculinities. Furthermore, it analyses the links between the groups’ experiences and practices and the wider sociopolitical context, arguing that a ‘postfeminist’ context, which can be seen as characterised by ambivalence towards feminism, presents challenges for feminist activists. This research responds to ongoing debates amongst feminists about whether and how men should be involved in the feminist movement (see, for example Luxton, 1993, Digby, 1998, Bryson, 1999, Elliott, 2008). The central argument of this thesis is that there is no simple answer to these questions. Mixed-gender feminist organising has both potential benefits and limitations in comparison to women’s groups and it may be more appropriate in some contexts, or for some tasks, than others. From a feminist perspective, what is important is to understand what may be at stake in including or excluding men from feminist activities and to make decisions about their involvement on this basis. This thesis outlines some of the issues which may be at stake, providing a valuable resource for feminist activists and theorists.