The employment of peer support providers in established welfare institutions has increased in recent years. This emerging trend involves former clients hired to use their personal experience as a professional tool, thereby combining the roles of client and professional. Meanwhile, new forms of knowledge and social interactions unfolding among peer support providers, clients, and professionals, as well as the dilemmas that may arise due to these interactions have not been researched. These comprise the purpose of the current PhD project, which investigates forms of knowledge, social relations, and interactions that evolve when peer support providers are integrated at two mental health institutions. Theoretically, the project combines theories on the social production of knowledge with symbolic interactionism. Methodologically, it employs ethnographic fieldwork including participant observation and interviews.