This paper presents findings of a qualitative interview study of the role of emotions in the professional identity of student teachers. Strong positive and negative emotions (mostly related to pupils and supervisors) were expressed about personal teaching experiences. The results confirm that emotions play an important role in social learning and, therefore, influence the development of professional identity. The two most important findings were that negative emotions exercised the strongest influence and that supervisors neglected the role of positive emotions as a support for learning. The study supports the concept that it is important for teacher educators to help student teachers understand their emotional experiences (focusing foremost on positive factors in their experience) and to develop the ability to express their own emotions in addition to understanding the emotions of others.