ABSTRACT This article introduces a special issue in Peacebuilding on researching masculinities during peace processes. It collates insights from feminist peace research, and research on gender and masculinities, to highlight how peace processes are necessarily also processes of gender re-negotiation and transformation. We argue that researching masculinities entails accounting for their plural circulation, complex and contradictory dynamics, and multiple effects. Researching masculinities additionally generates methodological dilemmas that require researchers’ reflexive engagement. The articles in the special issue address critical themes and topics pertaining to masculinities and peace across a wide range of participant experience in diverse contexts (including Bosnia, Indonesia, Liberia, Timor-Leste, Uganda, and the UK). We summarise authors’ critical and empirical contributions and chart their methodological innovations and strategies. We see plural masculine performances and identities not as obstacles to be overcome in/through research but as opportunities to generate discussion with research participants about the operability and impacts of gender.