The benefits of peer teaching have been intensively explored. However, there is still a lack of research in relation to student integration in higher education. The purpose of this study is to explore the relationship between peer teacher interaction and students' experiences of components of integration in the study programme. This comprises student and teacher interaction and support as well as identification with the programme. In addition, the aim is to explore how the students experience peer teachers as effecting their integration into the programme, and to explore how they visualise the relationship between students, teachers and peer teachers as part of the programme. Peer teaching was implemented in an introductory course in Environmental Sciences, in which the peer teachers were responsible for organising and teaching the course. The study was conducted with a mixed-method approach combining questionnaire data (N = 115), open-ended experiences (N = 80) and sketches (N = 80) done by the students participating in the course. The results show that peer teaching affected student integration in several ways. Practical implications and future research are also discussed.