My aim of this this thesis is to examine the assumed benefits of involving men and work on transforming masculinities when implementing the WPS (Women Peace and Security) agenda focusing on UNSCR (United Nations Security Council Resolutions) 1325 and 1820, in peacebuilding efforts and peacekeeping missions. The empirical findings derives from four semi- structured interviews with informants involved in implementing a masculinity perspective in UNSCR 1325, or informants that had conducted research of this area. A document analysis was also conducted to complement with the interviews and to dig deeper into how a focus on masculinities could be implemented. The document analysis consisted of training material from the Swedish Police force training on UNSCR 1325 for Swedish and international personnel going to UN Peacekeeping missions. The data was analysed with the theories radical feminism and R.W Connell’s masculinity theory. The thesis result indicate that the assumed benefits are multiple. The key reason to include men and to work on transforming masculinities could be that it would mean to take a holistic gender perspective, and to focus on the gendered drivers of conflict as well as the impacts of conflict.