The aim of this study was to examine teacher learning in terms of teachers' professional agency in the professional community of the school. Altogether 2310 Finnish comprehensive school teachers completed a survey. Results showed that teachers' active efforts to learn in the professional community and to promote school development cannot be explained, and hence reduced, to a single behavioral attribute. The findings indicated that teacher learning in terms of professional agency in the professional community consists of several elements including: skills, efficacy beliefs, and motivational factors, which entail transforming one's teaching practices, experiencing collective efficacy, constructing positive interdependency, the appreciation of mutual agreements, and using active strategies of help-seeking. The investigation also suggests that the use of modifying strategies is characteristic of both the teacher's professional agency as well as the strategies employed to reduce stress.