In North America, most of the institutional policies developed to combat gender violence have concerned the aftermath of violence, and predominantly the judicial sphere. They have led to better forensic care for victims, as well as financial support for organisations supporting victims. To a lesser extent, perpetrators of domestic violence have benefited from psycho-educational programs aimed at preventing recidivism, most often in conjunction with probation and prison services. This chapter examines educational programs implemented in Quebec, which have been created by researchers, educators, social workers, and psychologists, with the aim of preventing sexist and sexual violence by teaching communication techniques and sociological and psychological knowledge. Based on grey literature and on interviews with professionals working on prevention programs, the chapter analyses how ‘prevention’ is conceived. The chapter shows how programs are simultaneously institutionalised and rendered precarious. It also examines the forms of knowledge and expertise mobilised by violence-prevention professionals, and questions the role of psychology in public action against gender violence.