The purpose of this research is to seek the connection between professional development and an MA thesis research project, which is conducted as part of initial teacher education in Finland. This article examines the experiences of teachers with work experience, but without an official qualification, who recently completed their MA thesis. The theoretical framework is composed of professional development and a practitioner research approach. The study approaches the topic from a pragmatic viewpoint and it is realized as a qualitative interview study of 23 recently or nearly graduated teachers in Finland. The results indicate that MA thesis research may be viewed as practitioner research, when it is conducted on one's own work with the aim of developing the work, learning from the work, changing, or sharing information. The teachers were able to distinguish areas of professional development such as adjusting teaching, interaction skills, self-confidence, and criticalness, and many teachers saw an analogy between researching and teachers' work. (Contains 7 tables.)